    indexing
    	description: "Abstraction of a list in which you can add/modify/remove paths."
    	legal: "See notice at end of class."
    	status: "See notice at end of class."
    	date: "$Date: 2006-03-22 23:29:03 -0800 (Wed, 22 Mar 2006) $"
    	revision: "$Revision: 57641 $"

    class interface
    	EV_ADD_REMOVE_PATH_LIST

    create
    	make_with_parent (win: like parent_window)
    			-- Create an Add/Remove list.
    		require
    			win_not_void: win /= Void
    		ensure
    			parent_window_set: parent_window = win

    feature -- Access

    	accept_cursor: EV_POINTER_STYLE
    			-- `Result' is cursor displayed when the screen pointer is over a
    			-- target that accepts pebble during pick and drop.
    			-- (from EV_PICK_AND_DROPABLE)
    		require -- from  EV_ABSTRACT_PICK_AND_DROPABLE
    			True
    		ensure -- from EV_ABSTRACT_PICK_AND_DROPABLE
    			result_not_void: Result /= Void
    		ensure then -- from EV_PICK_AND_DROPABLE
    			bridge_ok: Result = implementation.accept_cursor

    	actual_drop_target_agent: FUNCTION [ANY, TUPLE [INTEGER_32, INTEGER_32], EV_ABSTRACT_PICK_AND_DROPABLE]
    			-- Overrides default drop target on a certain position.
    			-- If `Void', `Current' will use the default drop target.
    			-- (from EV_WIDGET)
    		require -- from EV_WIDGET
    			not_destroyed: not is_destroyed
    		ensure -- from EV_WIDGET
    			bridge_ok: Result = implementation.actual_drop_target_agent

    	add_actions: EV_NOTIFY_ACTION_SEQUENCE
    			-- Actions to be performed when `Add' is pressed then released.
    			-- (from EV_ADD_REMOVE_LIST)

    	background_color: EV_COLOR
    			-- Color displayed behind foreground features.
    			-- (from EV_COLORIZABLE)
    		require -- from EV_COLORIZABLE
    			not_destroyed: not is_destroyed
    		ensure -- from EV_COLORIZABLE
    			bridge_ok: Result.is_equal (implementation.background_color)

    	background_pixmap: EV_PIXMAP
    			-- `Result' is pixmap displayed on background of `Current'.
    			-- It is tessellated and fills whole of `Current'.
    			-- (from EV_CONTAINER)
    		require -- from EV_PIXMAPABLE
    			not_destroyed: not is_destroyed
    		ensure -- from EV_PIXMAPABLE
    			bridge_ok: (Result = Void and implementation.background_pixmap = Void) or Result.is_equal (implementation.background_pixmap)

    	cursor: EV_DYNAMIC_LIST_CURSOR [EV_WIDGET]
    			-- Current cursor position.
    			-- (from EV_DYNAMIC_LIST)
    		require -- from  CURSOR_STRUCTURE
    			True
    		ensure -- from CURSOR_STRUCTURE
    			cursor_not_void: Result /= Void
    		ensure then -- from EV_DYNAMIC_LIST
    			bridge_ok: Result.is_equal (implementation.cursor)

    	data: ANY
    			-- Arbitrary user data may be stored here.
    			-- (from EV_ANY)

    	default_key_processing_handler: PREDICATE [ANY, TUPLE [EV_KEY]] assign set_default_key_processing_handler
    			-- Agent used to determine whether the default key processing should occur for Current.
    			-- If agent returns True then default key processing continues as normal, False prevents
    			-- default key processing from occurring.
    			-- (from EV_WIDGET)
    		require -- from EV_WIDGET
    			not_destroyed: not is_destroyed
    		ensure -- from EV_WIDGET
    			bridge_ok: Result = implementation.default_key_processing_handler

    	deny_cursor: EV_POINTER_STYLE
    			-- `Result' is cursor displayed when the screen pointer is over a
    			-- target that does not accept pebble during pick and drop.
    			-- (from EV_PICK_AND_DROPABLE)
    		require -- from  EV_ABSTRACT_PICK_AND_DROPABLE
    			True
    		ensure -- from EV_ABSTRACT_PICK_AND_DROPABLE
    			result_not_void: Result /= Void
    		ensure then -- from EV_PICK_AND_DROPABLE
    			bridge_ok: Result = implementation.deny_cursor

    	first: like item
    			-- Item at first position
    			-- (from CHAIN)
    		require -- from CHAIN
    			not_empty: not vbox_is_empty

    	foreground_color: EV_COLOR
    			-- Color of foreground features like text.
    			-- (from EV_COLORIZABLE)
    		require -- from EV_COLORIZABLE
    			not_destroyed: not is_destroyed
    		ensure -- from EV_COLORIZABLE
    			bridge_ok: Result.is_equal (implementation.foreground_color)

    	generating_type: STRING_8
    			-- Name of current object's generating type
    			-- (type of which it is a direct instance)
    			-- (from ANY)

    	generator: STRING_8
    			-- Name of current object's generating class
    			-- (base class of the type of which it is a direct instance)
    			-- (from ANY)

    	has (v: like item): BOOLEAN
    			-- Does chain include `v'?
    			-- (Reference or object equality,
    			-- based on object_comparison.)
    			-- (from CHAIN)
    		require -- from  CONTAINER
    			True
    		ensure -- from CONTAINER
    			not_found_in_empty: Result implies not vbox_is_empty

    	has_recursive (an_item: like item): BOOLEAN
    			-- Does structure include `an_item' or
    			-- does any structure recursively included by structure,
    			-- include `an_item'.
    			-- (from EV_CONTAINER)
    		require -- from EV_CONTAINER
    			not_destroyed: not is_destroyed

    	help_context: FUNCTION [ANY, TUPLE, EV_HELP_CONTEXT]
    			-- Agent that evaluates to help context sent to help engine when help is requested
    			-- (from EV_HELP_CONTEXTABLE)
    		require -- from EV_HELP_CONTEXTABLE
    			not_destroyed: not is_destroyed
    		ensure -- from EV_HELP_CONTEXTABLE
    			bridge_ok: Result = implementation.help_context

    	i_th alias "[]" (i: INTEGER_32): like item
    			-- Item at `i'-th position.
    			-- (from EV_DYNAMIC_LIST)
    		require -- from TABLE
    			valid_key: valid_index (i)
    		ensure then -- from EV_DYNAMIC_LIST
    			bridge_ok: Result.is_equal (implementation.i_th (i))

    	frozen id_object (an_id: INTEGER_32): IDENTIFIED
    			-- Object associated with `an_id' (void if no such object)
    			-- (from IDENTIFIED)
    		ensure -- from IDENTIFIED
    			consistent: Result = Void or else Result.object_id = an_id

    	index: INTEGER_32
    			-- Current position.
    			-- (from EV_DYNAMIC_LIST)
    		require -- from  LINEAR
    			True
    		ensure then -- from EV_DYNAMIC_LIST
    			bridge_ok: Result = implementation.index

    	index_of (v: like item; i: INTEGER_32): INTEGER_32
    			-- Index of `i'th occurrence of `v'.
    			-- (from EV_DYNAMIC_LIST)
    		require -- from LINEAR
    			positive_occurrences: i > 0
    		ensure -- from LINEAR
    			non_negative_result: Result >= 0
    		ensure then -- from EV_DYNAMIC_LIST
    			bridge_ok: Result = implementation.index_of (v, i)

    	is_docking_enabled: BOOLEAN
    			-- May `Current' be docked to?
    			-- If True, `Current' will accept docking
    			-- from a compatible EV_DOCKABLE_SOURCE.
    			-- (from EV_DOCKABLE_TARGET)
    		require -- from EV_DOCKABLE_TARGET
    			not_destroyed: not is_destroyed
    		ensure -- from EV_DOCKABLE_TARGET
    			bridge_ok: Result = implementation.is_docking_enabled

    	item: EV_WIDGET
    			-- Item at current position.
    			-- (from EV_DYNAMIC_LIST)
    		require -- from TRAVERSABLE
    			not_off: not off
    		require -- from ACTIVE
    			readable: readable
    		require -- from EV_CONTAINER
    			not_destroyed: not is_destroyed
    			readable: readable
    		ensure -- from EV_CONTAINER
    			bridge_ok: Result = implementation.item
    		ensure then -- from EV_DYNAMIC_LIST
    			not_void: Result /= Void
    			bridge_ok: Result.is_equal (implementation.item)

    	last: like item
    			-- Item at last position
    			-- (from CHAIN)
    		require -- from CHAIN
    			not_empty: not vbox_is_empty

    	list: EV_LIST
    			-- List containing items user want to add/remove.
    			-- (from EV_ADD_REMOVE_LIST)

    	modify_actions: EV_NOTIFY_ACTION_SEQUENCE
    			-- Actions to be performed when `Apply' is pressed then released.
    			-- (from EV_ADD_REMOVE_LIST)

    	frozen object_id: INTEGER_32
    			-- Unique for current object in any given session
    			-- (from IDENTIFIED)
    		ensure -- from IDENTIFIED
    			valid_id: id_object (Result) = Current

    	sequential_occurrences (v: like item): INTEGER_32
    			-- Number of times `v' appears.
    			-- (Reference or object equality,
    			-- based on object_comparison.)
    			-- (from LINEAR)
    		require -- from  BAG
    			True
    		ensure -- from BAG
    			non_negative_occurrences: Result >= 0

    	parent: EV_CONTAINER
    			-- Contains `Current'.
    			-- (from EV_WIDGET)
    		require -- from EV_CONTAINABLE
    			not_destroyed: not is_destroyed
    		ensure then -- from EV_WIDGET
    			bridge_ok: Result = implementation.parent

    	parent_window: EV_WINDOW
    			-- Parent window in which browsing dialogs will be modal to.

    	path_field: EV_PATH_FIELD
    			-- Entry where path will be inserted.

    	pebble: ANY
    			-- Data to be transported by pick and drop mechanism.
    			-- (from EV_PICK_AND_DROPABLE)
    		require -- from  EV_ABSTRACT_PICK_AND_DROPABLE
    			True
    		ensure then -- from EV_PICK_AND_DROPABLE
    			bridge_ok: Result = implementation.pebble

    	pebble_function: FUNCTION [ANY, TUPLE, ANY]
    			-- Returns data to be transported by pick and drop mechanism.
    			-- (from EV_PICK_AND_DROPABLE)
    		require -- from  EV_ABSTRACT_PICK_AND_DROPABLE
    			True
    		ensure then -- from EV_PICK_AND_DROPABLE
    			bridge_ok: Result = implementation.pebble_function

    	pebble_positioning_enabled: BOOLEAN
    			-- If `True' then pick and drop start coordinates are
    			-- pebble_x_position, pebble_y_position.
    			-- If `False' then pick and drop start coordinates are
    			-- the pointer coordinates.
    			-- (from EV_PICK_AND_DROPABLE)
    		require -- from EV_PICK_AND_DROPABLE
    			not_destroyed: not is_destroyed
    		ensure then -- from EV_PICK_AND_DROPABLE
    			bridge_ok: Result = implementation.pebble_positioning_enabled

    	pebble_x_position: INTEGER_32
    			-- Initial x position for pick and drop relative to `Current'.
    			-- (from EV_PICK_AND_DROPABLE)
    		require -- from EV_PICK_AND_DROPABLE
    			not_destroyed: not is_destroyed
    		ensure then -- from EV_PICK_AND_DROPABLE
    			bridge_ok: Result = implementation.pebble_x_position

    	pebble_y_position: INTEGER_32
    			-- Initial y position for pick and drop relative to `Current'.
    			-- (from EV_PICK_AND_DROPABLE)
    		require -- from EV_PICK_AND_DROPABLE
    			not_destroyed: not is_destroyed
    		ensure then -- from EV_PICK_AND_DROPABLE
    			bridge_ok: Result = implementation.pebble_y_position

    	pointer_position: EV_COORDINATE
    			-- Position of the screen pointer relative to `Current'.
    			-- (from EV_WIDGET)
    		require -- from EV_WIDGET
    			not_destroyed: not is_destroyed
    			is_show_requested: is_show_requested

    	pointer_style: EV_POINTER_STYLE
    			-- Cursor displayed when pointer is over this widget.
    			-- (from EV_WIDGET)
    		require -- from EV_WIDGET
    			not_destroyed: not is_destroyed

    	real_target: EV_DOCKABLE_TARGET
    			-- `Result' is target used during a dockable transport if
    			-- mouse pointer is above `Current'.
    			-- (from EV_WIDGET)
    		require -- from EV_WIDGET
    			not_destroyed: not is_destroyed
    		ensure -- from EV_WIDGET
    			bridge_ok: Result = implementation.real_target

    	remove_actions: EV_NOTIFY_ACTION_SEQUENCE
    			-- Actions to be performed when `Delete' is pressed then released.
    			-- (from EV_ADD_REMOVE_LIST)

    	retrieve_item_by_data (some_data: ANY; should_compare_objects: BOOLEAN): EV_WIDGET
    			-- `Result' is first item in `Current' with data
    			-- matching `some_data'. Compare objects if
    			-- `should_compare_objects' otherwise compare references.
    			-- (from EV_DYNAMIC_LIST)
    		ensure -- from EV_DYNAMIC_LIST
    			not_found_in_empty: Result /= Void implies not vbox_is_empty
    			index_not_changed: old index = index

    	retrieve_items_by_data (some_data: ANY; should_compare_objects: BOOLEAN): ARRAYED_LIST [EV_WIDGET]
    			-- `Result' is all items in `Current' with data
    			-- matching `some_data'. Compare objects if
    			-- `should_compare_objects' otherwise compare references.
    			-- (from EV_DYNAMIC_LIST)
    		ensure -- from EV_DYNAMIC_LIST
    			result_not_void: Result /= Void
    			not_found_in_empty: not Result.is_empty implies not vbox_is_empty
    			index_not_changed: old index = index

    	target_name: STRING_GENERAL
    			-- Optional textual name describing `Current' pick and drop hole.
    			-- (from EV_ABSTRACT_PICK_AND_DROPABLE)

    	text_field: EV_TEXT_FIELD
    			-- Text field used to interact with list.
    			-- (from EV_ADD_REMOVE_LIST)

    	veto_dock_function: FUNCTION [ANY, TUPLE [EV_DOCKABLE_SOURCE], BOOLEAN]
    			-- Function to determine whether current dock is allowed.
    			-- If `Result' is `True', dock will be disallowed.
    			-- (from EV_DOCKABLE_TARGET)
    		require -- from EV_DOCKABLE_TARGET
    			not_destroyed: not is_destroyed
    		ensure -- from EV_DOCKABLE_TARGET
    			bridge_ok: Result = implementation.veto_dock_function

    	infix "@" (i: INTEGER_32): like item assign put_i_th
    			-- Item at `i'-th position
    			-- Was declared in CHAIN as synonym of i_th.
    			-- (from CHAIN)
    		require -- from TABLE
    			valid_key: valid_index (i)

    feature -- Measurement

    	client_height: INTEGER_32
    			-- Height of the area available to children in pixels.
    			-- (from EV_CONTAINER)
    		require -- from EV_CONTAINER
    			not_destroyed: not is_destroyed
    		ensure -- from EV_CONTAINER
    			bridge_ok: Result = implementation.client_height

    	client_width: INTEGER_32
    			-- Width of the area available to children in pixels.
    			-- (from EV_CONTAINER)
    		require -- from EV_CONTAINER
    			not_destroyed: not is_destroyed
    		ensure -- from EV_CONTAINER
    			bridge_ok: Result = implementation.client_width

    	vbox_count: INTEGER_32
    			-- Number of items.
    			-- (from EV_DYNAMIC_LIST)
    		require -- from  FINITE
    			True
    		require -- from  SET
    			True
    		require -- from EV_CONTAINER
    			not_destroyed: not is_destroyed
    		ensure then -- from EV_DYNAMIC_LIST
    			bridge_ok: Result = implementation.count

    	index_set: INTEGER_INTERVAL
    			-- Range of acceptable indexes
    			-- (from CHAIN)
    		require -- from  INDEXABLE
    			True
    		ensure -- from INDEXABLE
    			not_void: Result /= Void
    		ensure then -- from CHAIN
    			count_definition: Result.count = vbox_count

    	occurrences (v: like item): INTEGER_32
    			-- Number of times `v' appears.
    			-- (Reference or object equality,
    			-- based on object_comparison.)
    			-- (from CHAIN)
    		require -- from  BAG
    			True
    		require -- from  LINEAR
    			True
    		ensure -- from BAG
    			non_negative_occurrences: Result >= 0

    	screen_x: INTEGER_32
    			-- Horizontal offset relative to left of screen in pixels.
    			-- (from EV_WIDGET)
    		require -- from EV_WIDGET
    			not_destroyed: not is_destroyed
    		ensure -- from EV_WIDGET
    			bridge_ok: Result = implementation.screen_x

    	screen_y: INTEGER_32
    			-- Vertical offset relative to top of screen in pixels.
    			-- (from EV_WIDGET)
    		require -- from EV_WIDGET
    			not_destroyed: not is_destroyed
    		ensure -- from EV_WIDGET
    			bridge_ok: Result = implementation.screen_y

    feature -- Comparison

    	frozen deep_equal (some: ANY; other: like arg #1): BOOLEAN
    			-- Are `some' and `other' either both void
    			-- or attached to isomorphic object structures?
    			-- (from ANY)
    		ensure -- from ANY
    			shallow_implies_deep: standard_equal (some, other) implies Result
    			both_or_none_void: (some = Void) implies (Result = (other = Void))
    			same_type: (Result and (some /= Void)) implies some.same_type (other)
    			symmetric: Result implies deep_equal (other, some)

    	frozen equal (some: ANY; other: like arg #1): BOOLEAN
    			-- Are `some' and `other' either both void or attached
    			-- to objects considered equal?
    			-- (from ANY)
    		ensure -- from ANY
    			definition: Result = (some = Void and other = Void) or else ((some /= Void and other /= Void) and then some.is_equal (other))

    	is_equal (other: like Current): BOOLEAN
    			-- Does `other' contain the same elements?
    			-- (from LIST)
    		require -- from ANY
    			other_not_void: other /= Void
    		ensure -- from ANY
    			symmetric: Result implies other.is_equal (Current)
    			consistent: standard_is_equal (other) implies Result
    		ensure then -- from LIST
    			indices_unchanged: index = old index and other.index = old other.index
    			true_implies_same_size: Result implies vbox_count = other.vbox_count

    	frozen standard_equal (some: ANY; other: like arg #1): BOOLEAN
    			-- Are `some' and `other' either both void or attached to
    			-- field-by-field identical objects of the same type?
    			-- Always uses default object comparison criterion.
    			-- (from ANY)
    		ensure -- from ANY
    			definition: Result = (some = Void and other = Void) or else ((some /= Void and other /= Void) and then some.standard_is_equal (other))

    	frozen standard_is_equal (other: like Current): BOOLEAN
    			-- Is `other' attached to an object of the same type
    			-- as current object, and field-by-field identical to it?
    			-- (from ANY)
    		require -- from ANY
    			other_not_void: other /= Void
    		ensure -- from ANY
    			same_type: Result implies same_type (other)
    			symmetric: Result implies other.standard_is_equal (Current)

    feature -- Status report

    	after: BOOLEAN
    			-- Is there no valid cursor position to the right of cursor?
    			-- (from LIST)
    		require -- from  LINEAR
    			True

    	before: BOOLEAN
    			-- Is there no valid cursor position to the left of cursor?
    			-- (from LIST)
    		require -- from  BILINEAR
    			True

    	border_width: INTEGER_32
    			-- Width of border around container in pixels.
    			-- (from EV_BOX)
    		require -- from EV_BOX
    			not_destroyed: not is_destroyed
    		ensure -- from EV_BOX
    			bridge_ok: Result = implementation.border_width
    			positive: Result >= 0

    	conforms_to (other: ANY): BOOLEAN
    			-- Does type of current object conform to type
    			-- of `other' (as per Eiffel: The Language, chapter 13)?
    			-- (from ANY)
    		require -- from ANY
    			other_not_void: other /= Void

    	exhausted: BOOLEAN
    			-- Has structure been completely explored?
    			-- (from LINEAR)
    		ensure -- from LINEAR
    			exhausted_when_off: off implies Result

    	extendible: BOOLEAN is True
    			-- May new items be added? (Answer: yes.)
    			-- (from DYNAMIC_CHAIN)

    	full: BOOLEAN is False
    			-- Is structured filled to capacity? (Answer: no.)
    			-- (from EV_DYNAMIC_LIST)

    	has_capture: BOOLEAN
    			-- Does widget have capture?
    			-- (from EV_WIDGET)
    		require -- from EV_WIDGET
    			not_destroyed: not is_destroyed
    		ensure -- from EV_WIDGET
    			bridge_ok: Result = implementation.has_capture

    	has_focus: BOOLEAN
    			-- Does widget have the keyboard focus?
    			-- (from EV_WIDGET)
    		require -- from EV_WIDGET
    			not_destroyed: not is_destroyed
    		ensure -- from EV_WIDGET
    			bridge_ok: Result = implementation.has_focus

    	frozen id_freed: BOOLEAN
    			-- Has `Current' been removed from the table?
    			-- (from IDENTIFIED)

    	is_displayed: BOOLEAN
    			-- Is `Current' visible on the screen?
    			-- `True' when show requested and parent displayed.
    			-- (from EV_WIDGET)
    		require -- from EV_WIDGET
    			not_destroyed: not is_destroyed
    		ensure -- from EV_WIDGET
    			bridge_ok: Result = implementation.is_displayed

    	is_dockable: BOOLEAN
    			-- Is `Current' dockable?
    			-- If `True', then `Current' may be dragged
    			-- from its current parent.
    			-- (from EV_DOCKABLE_SOURCE)
    		require -- from EV_DOCKABLE_SOURCE
    			not_destroyed: not is_destroyed
    		ensure -- from EV_DOCKABLE_SOURCE
    			bridge_ok: Result = implementation.is_dockable

    	vbox_is_empty: BOOLEAN
    			-- Is structure empty?
    			-- (from FINITE)
    		require -- from  CONTAINER
    			True

    	is_external_docking_enabled: BOOLEAN
    			-- Is `Current' able to be docked into an EV_DOCKABLE_DIALOG
    			-- When there is no valid EV_DRAGABLE_TARGET upon completion
    			-- of transport?
    			-- (from EV_DOCKABLE_SOURCE)
    		require -- from EV_DOCKABLE_SOURCE
    			not_destroyed: not is_destroyed
    		ensure -- from EV_DOCKABLE_SOURCE
    			bridge_ok: Result = implementation.is_external_docking_enabled

    	is_external_docking_relative: BOOLEAN
    			-- Will dockable dialog displayed when `Current' is docked externally
    			-- be displayed relative to parent window of `Current'?
    			-- Otherwise displayed as a standard window.
    			-- (from EV_DOCKABLE_SOURCE)
    		require -- from EV_DOCKABLE_SOURCE
    			not_destroyed: not is_destroyed
    		ensure -- from EV_DOCKABLE_SOURCE
    			bridge_ok: Result = implementation.is_external_docking_relative

    	is_homogeneous: BOOLEAN
    			-- Are all items forced to have same dimensions.
    			-- (from EV_BOX)
    		require -- from EV_BOX
    			not_destroyed: not is_destroyed
    		ensure -- from EV_BOX
    			bridge_ok: Result = implementation.is_homogeneous

    	is_inserted (v: EV_WIDGET): BOOLEAN
    			-- Has `v' been inserted by the most recent insertion?
    			-- (By default, the value returned is equivalent to calling
    			-- `has (v)'. However, descendants might be able to provide more
    			-- efficient implementations.)
    			-- (from COLLECTION)

    	is_item_expanded (an_item: EV_WIDGET): BOOLEAN
    			-- Is `an_item' expanded to occupy available spare space?
    			-- (from EV_BOX)
    		require -- from EV_BOX
    			not_destroyed: not is_destroyed
    			has_an_item: has (an_item)
    		ensure -- from EV_BOX
    			bridge_ok: Result = implementation.is_item_expanded (an_item)

    	is_sensitive: BOOLEAN
    			-- Is object sensitive to user input.
    			-- (from EV_SENSITIVE)
    		require -- from EV_SENSITIVE
    			not_destroyed: not is_destroyed
    		ensure -- from EV_SENSITIVE
    			bridge_ok: Result = implementation.user_is_sensitive

    	is_show_requested: BOOLEAN
    			-- Will `Current' be displayed when its parent is?
    			-- See also is_displayed.
    			-- (from EV_WIDGET)
    		require -- from EV_WIDGET
    			not_destroyed: not is_destroyed
    		ensure -- from EV_WIDGET
    			bridge_ok: Result = implementation.is_show_requested

    	isfirst: BOOLEAN
    			-- Is cursor at first position?
    			-- (from CHAIN)
    		ensure -- from CHAIN
    			valid_position: Result implies not vbox_is_empty

    	islast: BOOLEAN
    			-- Is cursor at last position?
    			-- (from CHAIN)
    		ensure -- from CHAIN
    			valid_position: Result implies not vbox_is_empty

    	merged_radio_button_groups: ARRAYED_LIST [EV_CONTAINER]
    			-- `Result' is all other radio button groups
    			-- merged with `Current'. Void if no other containers
    			-- are merged.
    			-- (from EV_CONTAINER)
    		require -- from EV_CONTAINER
    			not_destroyed: not is_destroyed
    		ensure -- from EV_CONTAINER
    			not_is_empty: Result /= Void implies not Result.is_empty

    	mode_is_drag_and_drop: BOOLEAN
    			-- Is the user interface mode drag and drop?
    			-- (from EV_PICK_AND_DROPABLE)
    		require -- from EV_PICK_AND_DROPABLE
    			not_destroyed: not is_destroyed
    		ensure then -- from EV_PICK_AND_DROPABLE
    			bridge_ok: Result = implementation.mode_is_drag_and_drop

    	mode_is_pick_and_drop: BOOLEAN
    			-- Is the user interface mode pick and drop?
    			-- (from EV_PICK_AND_DROPABLE)
    		require -- from EV_PICK_AND_DROPABLE
    			not_destroyed: not is_destroyed
    		ensure then -- from EV_PICK_AND_DROPABLE
    			bridge_ok: Result = implementation.mode_is_pick_and_drop

    	mode_is_target_menu: BOOLEAN
    			-- Is the user interface mode a pop-up menu of targets?
    			-- (from EV_PICK_AND_DROPABLE)
    		require -- from EV_PICK_AND_DROPABLE
    			not_destroyed: not is_destroyed
    		ensure then -- from EV_PICK_AND_DROPABLE
    			bridge_ok: Result = implementation.mode_is_target_menu

    	off: BOOLEAN
    			-- Is there no current item?
    			-- (from CHAIN)
    		require -- from  TRAVERSABLE
    			True

    	padding: INTEGER_32
    			-- Space between children in pixels.
    			-- Was declared in EV_BOX as synonym of padding_width.
    			-- (from EV_BOX)
    		require -- from EV_BOX
    			not_destroyed: not is_destroyed
    		ensure -- from EV_BOX
    			bridge_ok: Result = implementation.padding
    			positive: Result >= 0

    	padding_width: INTEGER_32
    			-- Space between children in pixels.
    			-- Was declared in EV_BOX as synonym of padding.
    			-- (from EV_BOX)
    		require -- from EV_BOX
    			not_destroyed: not is_destroyed
    		ensure -- from EV_BOX
    			bridge_ok: Result = implementation.padding
    			positive: Result >= 0

    	prunable: BOOLEAN
    			-- May items be removed? (Answer: yes.)
    			-- (from DYNAMIC_CHAIN)
    		require -- from  COLLECTION
    			True

    	readable: BOOLEAN
    			-- Is there a current item that may be read?
    			-- (from SEQUENCE)
    		require -- from  ACTIVE
    			True
    		require -- from EV_CONTAINER
    			not_destroyed: not is_destroyed

    	real_source: EV_DOCKABLE_SOURCE
    			-- `Result' is source to be dragged
    			--  when a docking drag occurs on `Current'.
    			-- If `Void', `Current' is dragged.
    			-- (from EV_DOCKABLE_SOURCE)
    		require -- from EV_DOCKABLE_SOURCE
    			not_destroyed: not is_destroyed
    		ensure -- from EV_DOCKABLE_SOURCE
    			bridge_ok: Result = implementation.real_source

    	same_type (other: ANY): BOOLEAN
    			-- Is type of current object identical to type of `other'?
    			-- (from ANY)
    		require -- from ANY
    			other_not_void: other /= Void
    		ensure -- from ANY
    			definition: Result = (conforms_to (other) and other.conforms_to (Current))

    	valid_cursor (p: CURSOR): BOOLEAN
    			-- Can the cursor be moved to position `p'?
    			-- This is True if `p' conforms to EV_DYNAMIC_LIST_CURSOR and
    			-- if it points to an item, `Current' must have it.
    			-- (from EV_DYNAMIC_LIST)
    		require -- from  CURSOR_STRUCTURE
    			True
    		ensure then -- from EV_DYNAMIC_LIST
    			bridge_ok: Result = implementation.valid_cursor (p)

    	valid_cursor_index (i: INTEGER_32): BOOLEAN
    			-- Is `i' correctly bounded for cursor movement?
    			-- (from CHAIN)
    		ensure -- from CHAIN
    			valid_cursor_index_definition: Result = ((i >= 0) and (i <= vbox_count + 1))

    	valid_index (i: INTEGER_32): BOOLEAN
    			-- Is `i' within allowable bounds?
    			-- (from CHAIN)
    		require -- from  TABLE
    			True
    		ensure then -- from INDEXABLE
    			only_if_in_index_set: Result implies ((i >= index_set.lower) and (i <= index_set.upper))
    		ensure then -- from CHAIN
    			valid_index_definition: Result = ((i >= 1) and (i <= vbox_count))

    	writable: BOOLEAN
    			-- Is there a current item that may be modified?
    			-- (from SEQUENCE)
    		require -- from  ACTIVE
    			True
    		require -- from EV_CONTAINER
    			not_destroyed: not is_destroyed

    feature -- Status setting

    	center_pointer
    			-- Position screen pointer over center of `Current'.
    			-- (from EV_WIDGET)
    		require -- from EV_WIDGET
    			not_destroyed: not is_destroyed

    	disable_capture
    			-- Disable grab of all user input events.
    			-- (from EV_WIDGET)
    		require -- from EV_WIDGET
    			not_destroyed: not is_destroyed
    		ensure -- from EV_WIDGET
    			not_has_capture: not has_capture

    	disable_dockable
    			-- Ensure `Current' is not dockable.
    			-- (from EV_DOCKABLE_SOURCE)
    		require -- from EV_DOCKABLE_SOURCE
    			not_destroyed: not is_destroyed
    		ensure -- from EV_DOCKABLE_SOURCE
    			not_is_dockable: not is_dockable

    	disable_docking
    			-- Ensure is_docking_enabled is False.
    			-- `Current' will not accept docking.
    			-- (from EV_DOCKABLE_TARGET)
    		require -- from EV_DOCKABLE_TARGET
    			not_destroyed: not is_destroyed
    		ensure -- from EV_DOCKABLE_TARGET
    			not_dockable: not is_docking_enabled

    	disable_external_docking
    			-- Assign `False' to is_external_docking_enabled.
    			-- Forbid `Current' to be docked into an EV_DOCKABLE_DIALOG
    			-- When there is no valid EV_DRAGABLE_TARGET upon completion
    			-- of transport.
    			-- (from EV_DOCKABLE_SOURCE)
    		require -- from EV_DOCKABLE_SOURCE
    			not_destroyed: not is_destroyed
    			is_dockable: is_dockable
    		ensure -- from EV_DOCKABLE_SOURCE
    			not_externally_dockable: not is_external_docking_enabled

    	disable_external_docking_relative
    			-- Assign `False' to is_external_docking_relative, ensuring that
    			-- a dockable dialog displayed when `Current' is docked externally
    			-- is displayed as a standard window.
    			-- (from EV_DOCKABLE_SOURCE)
    		require -- from EV_DOCKABLE_SOURCE
    			not_destroyed: not is_destroyed
    			external_docking_enabled: is_external_docking_enabled
    		ensure -- from EV_DOCKABLE_SOURCE
    			external_docking_not_relative: not is_external_docking_relative

    	disable_homogeneous
    			-- Allow items to have different dimensions.
    			-- (from EV_BOX)
    		require -- from EV_BOX
    			not_destroyed: not is_destroyed
    		ensure -- from EV_BOX
    			not_is_homogeneous: not is_homogeneous

    	disable_item_expand (an_item: EV_WIDGET)
    			-- Do not expand `an_item' to occupy available spare space.
    			-- (from EV_BOX)
    		require -- from EV_BOX
    			not_destroyed: not is_destroyed
    			has_an_item: has (an_item)
    		ensure -- from EV_BOX
    			not_an_item_expanded: not is_item_expanded (an_item)

    	disable_pebble_positioning
    			-- Assign `False' to pebble_positioning_enabled.
    			-- The pick and drop will start at the pointer position.
    			-- (from EV_PICK_AND_DROPABLE)
    		require -- from EV_PICK_AND_DROPABLE
    			not_destroyed: not is_destroyed
    		ensure -- from EV_PICK_AND_DROPABLE
    			pebble_positioning_updated: not pebble_positioning_enabled

    	disable_sensitive
    			-- Make object non-sensitive to user input.
    			-- (from EV_SENSITIVE)
    		require -- from EV_SENSITIVE
    			not_destroyed: not is_destroyed
    		ensure -- from EV_SENSITIVE
    			is_unsensitive: not is_sensitive

    	enable_capture
    			-- Grab all user input events (mouse and keyboard).
    			-- disable_capture must be called to resume normal input handling.
    			-- (from EV_WIDGET)
    		require -- from EV_WIDGET
    			not_destroyed: not is_destroyed
    			is_displayed: is_displayed
    		ensure -- from EV_WIDGET
    			has_capture: has_capture

    	enable_dockable
    			-- Ensure `Current' is dockable.
    			-- (from EV_DOCKABLE_SOURCE)
    		require -- from EV_DOCKABLE_SOURCE
    			not_destroyed: not is_destroyed
    		ensure -- from EV_DOCKABLE_SOURCE
    			is_dockable: is_dockable

    	enable_docking
    			-- Ensure is_docking_enabled is True.
    			-- (from EV_DOCKABLE_TARGET)
    		require -- from EV_DOCKABLE_TARGET
    			not_destroyed: not is_destroyed
    		ensure -- from EV_DOCKABLE_TARGET
    			is_dockable: is_docking_enabled

    	enable_external_docking
    			-- Assign `True' to is_external_docking_enabled.
    			-- Allows `Current' to be docked into an EV_DOCKABLE_DIALOG
    			-- When there is no valid EV_DRAGABLE_TARGET upon completion
    			-- of transport.
    			-- (from EV_DOCKABLE_SOURCE)
    		require -- from EV_DOCKABLE_SOURCE
    			not_destroyed: not is_destroyed
    			is_dockable: is_dockable
    		ensure -- from EV_DOCKABLE_SOURCE
    			is_externally_dockable: is_external_docking_enabled

    	enable_external_docking_relative
    			-- Assign `True' to is_external_docking_relative, ensuring that
    			-- a dockable dialog displayed when `Current' is docked externally
    			-- is displayed relative to the top level window.
    			-- (from EV_DOCKABLE_SOURCE)
    		require -- from EV_DOCKABLE_SOURCE
    			not_destroyed: not is_destroyed
    			external_docking_enabled: is_external_docking_enabled
    		ensure -- from EV_DOCKABLE_SOURCE
    			external_docking_not_relative: is_external_docking_relative

    	enable_homogeneous
    			-- Force all items to have same dimensions.
    			-- (from EV_BOX)
    		require -- from EV_BOX
    			not_destroyed: not is_destroyed
    		ensure -- from EV_BOX
    			is_homogeneous: is_homogeneous

    	enable_item_expand (an_item: EV_WIDGET)
    			-- Expand `an_item' to occupy available spare space.
    			-- (from EV_BOX)
    		require -- from EV_BOX
    			not_destroyed: not is_destroyed
    			has_an_item: has (an_item)
    		ensure -- from EV_BOX
    			an_item_expanded: is_item_expanded (an_item)

    	enable_pebble_positioning
    			-- Assign `True' to pebble_positioning_enabled.
    			-- Use pebble_x_position and pebble_y_position as the initial coordinates
    			-- for the pick and drop in pixels relative to `Current'.
    			-- (from EV_PICK_AND_DROPABLE)
    		require -- from EV_PICK_AND_DROPABLE
    			not_destroyed: not is_destroyed
    		ensure -- from EV_PICK_AND_DROPABLE
    			pebble_positioning_updated: pebble_positioning_enabled

    	enable_sensitive
    			-- Make object sensitive to user input.
    			-- (from EV_SENSITIVE)
    		require -- from EV_SENSITIVE
    			not_destroyed: not is_destroyed
    		ensure -- from EV_SENSITIVE
    			is_sensitive: (parent = Void or parent_is_sensitive) implies is_sensitive

    	hide
    			-- Request that `Current' not be displayed even when its parent is.
    			-- If successful, make is_show_requested `False'.
    			-- (from EV_WIDGET)
    		require -- from EV_WIDGET
    			not_destroyed: not is_destroyed

    	merge_radio_button_groups (other: EV_CONTAINER)
    			-- Merge `Current' radio button group with that of `other'.
    			-- (from EV_CONTAINER)
    		require -- from EV_CONTAINER
    			not_destroyed: not is_destroyed
    			other_not_void: other /= Void

    	remove_default_key_processing_handler
    			-- Ensure default_key_processing_handler is Void.
    			-- (from EV_WIDGET)
    		require -- from EV_WIDGET
    			not_destroyed: not is_destroyed
    		ensure -- from EV_WIDGET
    			default_key_processing_handler_removed: default_key_processing_handler = Void

    	remove_pebble
    			-- Make pebble `Void' and pebble_function `Void,
    			-- Removing transport.
    			-- (from EV_PICK_AND_DROPABLE)
    		ensure -- from EV_ABSTRACT_PICK_AND_DROPABLE
    			pebble_removed: pebble = Void and pebble_function = Void

    	remove_real_source
    			-- Ensure real_source is `Void'.
    			-- (from EV_DOCKABLE_SOURCE)
    		require -- from EV_DOCKABLE_SOURCE
    			not_destroyed: not is_destroyed
    		ensure -- from EV_DOCKABLE_SOURCE
    			real_source_void: real_source = Void

    	remove_real_target
    			-- Ensure real_target is `Void'.
    			-- (from EV_WIDGET)
    		require -- from EV_WIDGET
    			not_destroyed: not is_destroyed
    		ensure -- from EV_WIDGET
    			real_target_void: real_target = Void

    	set_accept_cursor (a_cursor: like accept_cursor)
    			-- Set `a_cursor' to be displayed when the screen pointer is over a
    			-- target that accepts pebble during pick and drop.
    			-- (from EV_PICK_AND_DROPABLE)
    		require -- from EV_ABSTRACT_PICK_AND_DROPABLE
    			a_cursor_not_void: a_cursor /= Void
    		ensure -- from EV_ABSTRACT_PICK_AND_DROPABLE
    			accept_cursor_assigned: accept_cursor.is_equal (a_cursor)

    	set_actual_drop_target_agent (an_agent: like actual_drop_target_agent)
    			-- Assign `an_agent' to actual_drop_target_agent.
    			-- (from EV_WIDGET)
    		require -- from EV_WIDGET
    			not_destroyed: not is_destroyed
    			an_agent_not_void: an_agent /= Void
    		ensure -- from EV_WIDGET
    			assigned: actual_drop_target_agent = an_agent

    	set_border_width (value: INTEGER_32)
    			-- Assign `value' to border_width.
    			-- (from EV_BOX)
    		require -- from EV_BOX
    			not_destroyed: not is_destroyed
    			positive_value: value >= 0
    		ensure -- from EV_BOX
    			border_width_assigned: border_width = value

    	set_default_colors
    			-- Set foreground and background color to their default values.
    			-- (from EV_COLORIZABLE)
    		require -- from EV_COLORIZABLE
    			not_destroyed: not is_destroyed

    	set_default_key_processing_handler (a_handler: like default_key_processing_handler)
    			-- Assign default_key_processing_handler to `a_handler'.
    			-- (from EV_WIDGET)
    		require -- from EV_WIDGET
    			not_destroyed: not is_destroyed

    	set_deny_cursor (a_cursor: like deny_cursor)
    			-- Set `a_cursor' to be displayed when the screen pointer is not
    			-- over a valid target.
    			-- (from EV_PICK_AND_DROPABLE)
    		require -- from EV_ABSTRACT_PICK_AND_DROPABLE
    			a_cursor_not_void: a_cursor /= Void
    		ensure -- from EV_ABSTRACT_PICK_AND_DROPABLE
    			deny_cursor_assigned: deny_cursor.is_equal (a_cursor)

    	set_drag_and_drop_mode
    			-- Set user interface mode to drag and drop.
    			-- (from EV_PICK_AND_DROPABLE)
    		require -- from EV_PICK_AND_DROPABLE
    			not_destroyed: not is_destroyed
    		ensure -- from EV_PICK_AND_DROPABLE
    			drag_and_drop_set: mode_is_drag_and_drop

    	set_focus
    			-- Grab keyboard focus.
    			-- (from EV_WIDGET)
    		require -- from EV_WIDGET
    			not_destroyed: not is_destroyed
    			is_displayed: is_displayed
    			is_sensitive: is_sensitive

    	set_padding (value: INTEGER_32)
    			-- Assign `value' to padding_width.
    			-- Was declared in EV_BOX as synonym of set_padding_width.
    			-- (from EV_BOX)
    		require -- from EV_BOX
    			not_destroyed: not is_destroyed
    			positive_value: value >= 0
    		ensure -- from EV_BOX
    			padding_assigned: padding = value

    	set_padding_width (value: INTEGER_32)
    			-- Assign `value' to padding_width.
    			-- Was declared in EV_BOX as synonym of set_padding.
    			-- (from EV_BOX)
    		require -- from EV_BOX
    			not_destroyed: not is_destroyed
    			positive_value: value >= 0
    		ensure -- from EV_BOX
    			padding_assigned: padding = value

    	set_pebble (a_pebble: like pebble)
    			-- Assign `a_pebble' to pebble.
    			-- Overrides set_pebble_function.
    			-- (from EV_PICK_AND_DROPABLE)
    		require -- from EV_ABSTRACT_PICK_AND_DROPABLE
    			a_pebble_not_void: a_pebble /= Void
    		ensure -- from EV_ABSTRACT_PICK_AND_DROPABLE
    			pebble_assigned: pebble = a_pebble

    	set_pebble_function (a_function: FUNCTION [ANY, TUPLE, ANY])
    			-- Set `a_function' to compute pebble.
    			-- It will be called once each time a pick occurs, the result
    			-- will be assigned to pebble for the duration of transport.
    			-- When a pick occurs, the pick position in widget coordinates,
    			-- <<x, y>> in pixels, is passed.
    			-- To handle this data use `a_function' of type
    			-- FUNCTION [ANY, TUPLE [INTEGER, INTEGER], ANY] and return the
    			-- pebble as a function of x and y.
    			-- Overrides set_pebble.
    			-- (from EV_PICK_AND_DROPABLE)
    		require -- from EV_ABSTRACT_PICK_AND_DROPABLE
    			a_function_not_void: a_function /= Void
    			a_function_takes_two_integer_open_operands: a_function.valid_operands ([1, 1])
    		ensure -- from EV_ABSTRACT_PICK_AND_DROPABLE
    			pebble_function_assigned: pebble_function = a_function

    	set_pebble_position (a_x, a_y: INTEGER_32)
    			-- Set the initial position for pick and drop
    			-- Coordinates are in pixels and are relative to position of `Current'.
    			-- Pebble_positioning_enabled must be `True' for the position to be used,
    			-- use enable_pebble_positioning.
    			-- (from EV_PICK_AND_DROPABLE)
    		require -- from EV_PICK_AND_DROPABLE
    			not_destroyed: not is_destroyed
    		ensure -- from EV_PICK_AND_DROPABLE
    			pebble_position_assigned: pebble_x_position = a_x and pebble_y_position = a_y

    	set_pick_and_drop_mode
    			-- Set user interface mode to pick and drop.
    			-- (from EV_PICK_AND_DROPABLE)
    		require -- from EV_PICK_AND_DROPABLE
    			not_destroyed: not is_destroyed
    		ensure -- from EV_PICK_AND_DROPABLE
    			pick_and_drop_set: mode_is_pick_and_drop

    	set_real_source (dockable_source: EV_DOCKABLE_SOURCE)
    			-- Assign `dockable_source' to real_source.
    			-- (from EV_DOCKABLE_SOURCE)
    		require -- from EV_DOCKABLE_SOURCE
    			not_destroyed: not is_destroyed
    			is_dockable: is_dockable
    			dockable_source_not_void: dockable_source /= Void
    			dockable_source_is_parent_recursive: source_has_current_recursive (dockable_source)
    		ensure -- from EV_DOCKABLE_SOURCE
    			real_source_assigned: real_source = dockable_source

    	set_real_target (a_target: EV_DOCKABLE_TARGET)
    			-- Assign `a_target' to real_target.
    			-- (from EV_WIDGET)
    		require -- from EV_WIDGET
    			not_destroyed: not is_destroyed
    			target_not_void: a_target /= Void
    		ensure -- from EV_WIDGET
    			assigned: real_target = a_target

    	set_target_menu_mode
    			-- Set user interface mode to pop-up menu of targets.
    			-- (from EV_PICK_AND_DROPABLE)
    		require -- from EV_PICK_AND_DROPABLE
    			not_destroyed: not is_destroyed
    		ensure -- from EV_PICK_AND_DROPABLE
    			target_menu_mode_set: mode_is_target_menu

    	set_target_name (a_name: STRING_GENERAL)
    			-- Assign `a_name' to target_name.
    			-- (from EV_ABSTRACT_PICK_AND_DROPABLE)
    		require -- from EV_ABSTRACT_PICK_AND_DROPABLE
    			a_name_not_void: a_name /= Void
    		ensure -- from EV_ABSTRACT_PICK_AND_DROPABLE
    			target_name_assigned: a_name /= target_name and a_name.is_equal (target_name)

    	set_veto_dock_function (a_function: FUNCTION [ANY, TUPLE [EV_DOCKABLE_SOURCE], BOOLEAN])
    			-- Assign `a_function' to veto_dock_function.
    			-- (from EV_DOCKABLE_TARGET)
    		require -- from EV_DOCKABLE_TARGET
    			not_destroyed: not is_destroyed
    			a_function_not_void: a_function /= Void
    		ensure -- from EV_DOCKABLE_TARGET
    			veto_function_set: veto_dock_function = a_function

    	show
    			-- Request that `Current' be displayed when its parent is.
    			-- `True' by default.
    			-- If successful, make is_show_requested `True'.
    			-- (from EV_WIDGET)
    		require -- from EV_WIDGET
    			not_destroyed: not is_destroyed

    	unmerge_radio_button_groups (other: EV_CONTAINER)
    			-- Remove `other' from radio button group of `Current'.
    			-- If no radio button of `other' was checked before removal
    			-- then first radio button contained will be checked.
    			-- (from EV_CONTAINER)
    		require -- from EV_CONTAINER
    			not_destroyed: not is_destroyed
    			other_is_merged: merged_radio_button_groups.has (other)
    		ensure -- from EV_CONTAINER
    			other_not_merged: other.merged_radio_button_groups = Void
    			not_contained_in_this_group: merged_radio_button_groups /= Void implies not merged_radio_button_groups.has (other)
    			other_first_radio_button_now_selected: not old other.has_selected_radio_button and old other.has_radio_button implies other.first_radio_button_selected
    			original_radio_button_still_selected: old has_selected_radio_button implies has_selected_radio_button
    			other_first_radio_button_now_selected: not old has_selected_radio_button and old other.has_radio_button and old merged_radio_button_groups.count = 1 and has_radio_button implies first_radio_button_selected
    			other_original_radio_button_still_selected: old other.has_selected_radio_button implies other.has_selected_radio_button

    feature -- Cursor movement

    	back
    			-- Move to previous position.
    			-- (from EV_DYNAMIC_LIST)
    		require -- from BILINEAR
    			not_before: not before

    	finish
    			-- Move cursor to last position.
    			-- (No effect if empty)
    			-- (from CHAIN)
    		require -- from  LINEAR
    			True
    		ensure then -- from CHAIN
    			at_last: not vbox_is_empty implies islast

    	forth
    			-- Move cursor to next position.
    			-- (from EV_DYNAMIC_LIST)
    		require -- from LINEAR
    			not_after: not after
    		ensure then -- from LIST
    			moved_forth: index = old index + 1

    	go_i_th (i: INTEGER_32)
    			-- Move cursor to `i'-th position.
    			-- (from EV_DYNAMIC_LIST)
    		require -- from CHAIN
    			valid_cursor_index: valid_cursor_index (i)
    		ensure -- from CHAIN
    			position_expected: index = i

    	go_to (p: CURSOR)
    			-- Move cursor to position `p'.
    			-- (from EV_DYNAMIC_LIST)
    		require -- from CURSOR_STRUCTURE
    			cursor_position_valid: valid_cursor (p)

    	move (i: INTEGER_32)
    			-- Move cursor `i' positions.
    			-- (from EV_DYNAMIC_LIST)
    		ensure -- from CHAIN
    			too_far_right: (old index + i > vbox_count) implies exhausted
    			too_far_left: (old index + i < 1) implies exhausted
    			expected_index: (not exhausted) implies (index = old index + i)

    	search (v: like item)
    			-- Move to first position (at or after current
    			-- position) where item and `v' are equal.
    			-- If structure does not include `v' ensure that
    			-- exhausted will be true.
    			-- (Reference or object equality,
    			-- based on object_comparison.)
    			-- (from BILINEAR)
    		ensure -- from LINEAR
    			object_found: (not exhausted and object_comparison) implies equal (v, item)
    			item_found: (not exhausted and not object_comparison) implies v = item

    	start
    			-- Move cursor to first position.
    			-- (from EV_DYNAMIC_LIST)
    		require -- from  TRAVERSABLE
    			True
    		ensure then -- from CHAIN
    			at_first: not vbox_is_empty implies isfirst
    		ensure then -- from EV_DYNAMIC_LIST
    			empty_implies_after: vbox_is_empty implies after

    feature -- Element change

    	append (s: SEQUENCE [like item])
    			-- Append a copy of `s'. Do not move cursor.
    			-- (from EV_DYNAMIC_LIST)
    		require -- from EV_DYNAMIC_LIST
    			not_destroyed: not is_destroyed
    			extendible: extendible
    			sequence_not_void: s /= Void
    			sequence_not_current: s /= Current
    			not_parented: not s.there_exists (agent (v: like item): BOOLEAN
    			)
    		ensure -- from EV_DYNAMIC_LIST
    			count_increased: old vbox_count + s.count = vbox_count
    			cursor_not_moved: (index = old index) or (after and old after)

    	extend (v: like item)
    			-- Add `v' to end. Do not move cursor.
    			-- Was declared in EV_DYNAMIC_LIST as synonym of force.
    			-- (from EV_DYNAMIC_LIST)
    		require -- from EV_CONTAINER
    			not_destroyed: not is_destroyed
    			extendible: extendible
    			v_not_void: v /= Void
    			v_parent_void: v.parent = Void
    			v_not_current: v /= Current
    			v_not_parent_of_current: not is_parent_recursive (v)
    			v_containable: may_contain (v)
    		require -- from EV_DYNAMIC_LIST
    			not_destroyed: not is_destroyed
    			extendible: extendible
    			v_not_void: v /= Void
    			v_parent_void: v.parent = Void
    			v_not_current: not same (v)
    			v_not_parent_of_current: not is_parent_recursive (v)
    		ensure -- from EV_CONTAINER
    			has_v: has (v)
    		ensure -- from EV_DYNAMIC_LIST
    			parent_is_current: v.parent = Current
    			v_is_last: v = last
    			count_increased: vbox_count = old vbox_count + 1
    			cursor_not_moved: (index = old index) or (after and old after)

    	fill (other: CONTAINER [EV_WIDGET])
    			-- Fill with as many items of `other' as possible.
    			-- The representations of `other' and current structure
    			-- need not be the same.
    			-- (from CHAIN)
    		require -- from COLLECTION
    			other_not_void: other /= Void
    			extendible: extendible

    	force (v: like item)
    			-- Add `v' to end. Do not move cursor.
    			-- Was declared in EV_DYNAMIC_LIST as synonym of extend.
    			-- (from EV_DYNAMIC_LIST)
    		require -- from EV_DYNAMIC_LIST
    			not_destroyed: not is_destroyed
    			extendible: extendible
    			v_not_void: v /= Void
    			v_parent_void: v.parent = Void
    			v_not_current: not same (v)
    			v_not_parent_of_current: not is_parent_recursive (v)
    		ensure -- from EV_DYNAMIC_LIST
    			parent_is_current: v.parent = Current
    			v_is_last: v = last
    			count_increased: vbox_count = old vbox_count + 1
    			cursor_not_moved: (index = old index) or (after and old after)

    	dl_force (v: like item)
    			-- Add `v' to end.
    			-- (from SEQUENCE)
    		require -- from SEQUENCE
    			extendible: extendible
    		ensure then -- from SEQUENCE
    			new_count: vbox_count = old vbox_count + 1
    			item_inserted: has (v)

    	merge_left (other: like Current)
    			-- Merge `other' into current structure before cursor
    			-- position. Do not move cursor. Empty `other'.
    			-- (from EV_DYNAMIC_LIST)
    		require -- from DYNAMIC_CHAIN
    			extendible: extendible
    			not_before: not before
    			other_exists: other /= Void
    			not_current: other /= Current
    		ensure -- from DYNAMIC_CHAIN
    			new_count: vbox_count = old vbox_count + old other.vbox_count
    			new_index: index = old index + old other.vbox_count
    			other_is_empty: other.vbox_is_empty

    	merge_right (other: like Current)
    			-- Merge `other' into current structure after cursor
    			-- position. Do not move cursor. Empty `other'.
    			-- (from EV_DYNAMIC_LIST)
    		require -- from DYNAMIC_CHAIN
    			extendible: extendible
    			not_after: not after
    			other_exists: other /= Void
    			not_current: other /= Current
    		ensure -- from DYNAMIC_CHAIN
    			new_count: vbox_count = old vbox_count + old other.vbox_count
    			same_index: index = old index
    			other_is_empty: other.vbox_is_empty

    	put (v: like item)
    			-- Replace current item by `v'.
    			-- (Synonym for replace)
    			-- (from CHAIN)
    		require -- from COLLECTION
    			extendible: extendible
    		require -- from EV_CONTAINER
    			not_destroyed: not is_destroyed
    			writable: writable
    			v_not_void: v /= Void
    			v_parent_void: v.parent = Void
    			v_not_current: v /= Current
    			v_not_parent_of_current: not is_parent_recursive (v)
    			v_containable: may_contain (v)
    		ensure -- from COLLECTION
    			item_inserted: is_inserted (v)
    		ensure then -- from SET
    			in_set_already: old has (v) implies (vbox_count = old vbox_count)
    			added_to_set: not old has (v) implies (vbox_count = old vbox_count + 1)
    		ensure then -- from CHAIN
    			same_count: vbox_count = old vbox_count
    		ensure -- from EV_CONTAINER
    			has_v: has (v)
    			not_has_old_item: not has (old item)

    	put_front (v: like item)
    			-- Add `v' at beginning. Do not move cursor.
    			-- (from EV_DYNAMIC_LIST)
    		require -- from EV_DYNAMIC_LIST
    			not_destroyed: not is_destroyed
    			extendible: extendible
    			v_not_void: v /= Void
    			v_parent_void: v.parent = Void
    			v_not_current: not same (v)
    			v_not_parent_of_current: not is_parent_recursive (v)
    		ensure -- from EV_DYNAMIC_LIST
    			parent_is_current: v.parent = Current
    			v_is_first: v = first
    			count_increased: vbox_count = old vbox_count + 1
    			cursor_not_moved: (index = old index + 1) or (before and old before)

    	put_i_th (v: like item; i: INTEGER_32)
    			-- Replace item at `i'-th position by `v'.
    			-- (from EV_DYNAMIC_LIST)
    		require -- from EV_DYNAMIC_LIST
    			not_destroyed: not is_destroyed
    			valid_index: i > 0 and i <= vbox_count
    			v_not_void: v /= Void
    			v_parent_void: v.parent = Void
    			v_not_current: not same (v)
    			v_not_parent_of_current: not is_parent_recursive (v)
    		ensure -- from EV_DYNAMIC_LIST
    			parent_is_current: v.parent = Current
    			item_replaced: v = i_th (i)
    			not_has_old_item: not has (old i_th (i))
    			old_item_parent_void: (old i_th (i)).parent = Void
    			count_same: vbox_count = old vbox_count
    			cursor_not_moved: index = old index

    	put_left (v: like item)
    			-- Add `v' to the left of cursor position. Do not move cursor.
    			-- (from EV_DYNAMIC_LIST)
    		require -- from EV_DYNAMIC_LIST
    			not_destroyed: not is_destroyed
    			extendible: extendible
    			not_before: not before
    			v_not_void: v /= Void
    			v_parent_void: v.parent = Void
    			v_not_current: not same (v)
    			v_not_parent_of_current: not is_parent_recursive (v)
    		ensure -- from EV_DYNAMIC_LIST
    			parent_is_current: v.parent = Current
    			v_at_index_plus_one: v = i_th (index - 1)
    			count_increased: vbox_count = old vbox_count + 1
    			cursor_not_moved: index = old index + 1

    	put_right (v: like item)
    			-- Add `v' to right of cursor position. Do not move cursor.
    			-- (from EV_DYNAMIC_LIST)
    		require -- from EV_DYNAMIC_LIST
    			not_destroyed: not is_destroyed
    			extendible: extendible
    			not_after: not after
    			v_not_void: v /= Void
    			v_parent_void: v.parent = Void
    			v_not_current: not same (v)
    			v_not_parent_of_current: not is_parent_recursive (v)
    		ensure -- from EV_DYNAMIC_LIST
    			parent_is_current: v.parent = Current
    			v_at_index_plus_one: v = i_th (index + 1)
    			count_increased: vbox_count = old vbox_count + 1
    			cursor_not_moved: index = old index

    	remove_help_context
    			-- Remove key press action associated with `EV_APPLICATION.help_key'.
    			-- (from EV_HELP_CONTEXTABLE)
    		require -- from EV_HELP_CONTEXTABLE
    			not_destroyed: not is_destroyed
    			help_context_not_void: help_context /= Void
    		ensure -- from EV_HELP_CONTEXTABLE
    			no_help_context: help_context = Void

    	remove_background_pixmap
    			-- Remove image displayed on `Current'.
    			-- (from EV_PIXMAPABLE)
    		require -- from EV_PIXMAPABLE
    			not_destroyed: not is_destroyed
    		ensure -- from EV_PIXMAPABLE
    			pixmap_removed: background_pixmap = Void

    	replace (v: like item)
    			-- Replace current item by `v'.
    			-- (from EV_DYNAMIC_LIST)
    		require -- from EV_CONTAINER
    			not_destroyed: not is_destroyed
    			writable: writable
    			v_not_void: v /= Void
    			v_parent_void: v.parent = Void
    			v_not_current: v /= Current
    			v_not_parent_of_current: not is_parent_recursive (v)
    			v_containable: may_contain (v)
    		require -- from EV_DYNAMIC_LIST
    			not_destroyed: not is_destroyed
    			writable: writable
    			v_not_void: v /= Void
    			v_parent_void: v.parent = Void
    			v_not_current: not same (v)
    			v_not_parent_of_current: not is_parent_recursive (v)
    		ensure -- from EV_CONTAINER
    			has_v: has (v)
    			not_has_old_item: not has (old item)
    		ensure -- from EV_DYNAMIC_LIST
    			parent_is_current: v.parent = Current
    			item_replaced: v = item
    			not_has_old_item: not has (old item)
    			old_item_parent_void: (old item).parent = Void
    			count_same: vbox_count = old vbox_count
    			cursor_not_moved: index = old index

    	set_background_color (a_color: like background_color)
    			-- Assign `a_color' to background_color.
    			-- (from EV_COLORIZABLE)
    		require -- from EV_COLORIZABLE
    			not_destroyed: not is_destroyed
    			a_color_not_void: a_color /= Void
    		ensure -- from EV_COLORIZABLE
    			background_color_assigned: background_color.is_equal (a_color)

    	set_data (some_data: like data)
    			-- Assign `some_data' to data.
    			-- (from EV_ANY)
    		require -- from EV_ANY
    			not_destroyed: not is_destroyed
    		ensure -- from EV_ANY
    			data_assigned: data = some_data

    	set_foreground_color (a_color: like foreground_color)
    			-- Assign `a_color' to foreground_color.
    			-- (from EV_COLORIZABLE)
    		require -- from EV_COLORIZABLE
    			not_destroyed: not is_destroyed
    			a_color_not_void: a_color /= Void
    		ensure -- from EV_COLORIZABLE
    			foreground_color_assigned: foreground_color.is_equal (a_color)

    	set_help_context (an_help_context: like help_context)
    			-- Assign `an_help_context' to help_context.
    			-- (from EV_HELP_CONTEXTABLE)
    		require -- from EV_HELP_CONTEXTABLE
    			not_destroyed: not is_destroyed
    			an_help_context_not_void: an_help_context /= Void
    		ensure -- from EV_HELP_CONTEXTABLE
    			help_context_assigned: help_context.is_equal (an_help_context)

    	set_minimum_height (a_minimum_height: INTEGER_32)
    			-- Set `a_minimum_height' in pixels to minimum_height.
    			-- If height is less than `a_minimum_height', resize.
    			-- From now, minimum_height is fixed and will not be changed
    			-- dynamically by the application anymore.
    			-- (from EV_WIDGET)
    		require -- from EV_WIDGET
    			not_destroyed: not is_destroyed
    			a_minimum_height_positive: a_minimum_height >= 0
    		ensure -- from EV_WIDGET
    			minimum_height_assigned: minimum_height = a_minimum_height
    			minimum_height_set_by_user_set: minimum_height_set_by_user

    	set_minimum_size (a_minimum_width, a_minimum_height: INTEGER_32)
    			-- Assign `a_minimum_height' to minimum_height
    			-- and `a_minimum_width' to minimum_width in pixels.
    			-- If width or height is less than minimum size, resize.
    			-- From now, minimum size is fixed and will not be changed
    			-- dynamically by the application anymore.
    			-- (from EV_WIDGET)
    		require -- from EV_WIDGET
    			not_destroyed: not is_destroyed
    			a_minimum_width_positive: a_minimum_width >= 0
    			a_minimum_height_positive: a_minimum_height >= 0
    		ensure -- from EV_WIDGET
    			minimum_width_assigned: minimum_width = a_minimum_width
    			minimum_height_assigned: minimum_height = a_minimum_height
    			minimum_height_set_by_user_set: minimum_height_set_by_user
    			minimum_width_set_by_user_set: minimum_width_set_by_user

    	set_minimum_width (a_minimum_width: INTEGER_32)
    			-- Assign `a_minimum_width' in pixels to minimum_width.
    			-- If width is less than `a_minimum_width', resize.
    			-- From now, minimum_width is fixed and will not be changed
    			-- dynamically by the application anymore.
    			-- (from EV_WIDGET)
    		require -- from EV_WIDGET
    			not_destroyed: not is_destroyed
    			a_minimum_width_positive: a_minimum_width >= 0
    		ensure -- from EV_WIDGET
    			minimum_width_assigned: minimum_width = a_minimum_width
    			minimum_width_set_by_user_set: minimum_width_set_by_user

    	set_background_pixmap (a_pixmap: EV_PIXMAP)
    			-- Display image of `a_pixmap' on `Current'.
    			-- Image of `pixmap' will be a copy of `a_pixmap'.
    			-- Image may be scaled in some descendents, i.e EV_TREE_ITEM
    			-- See EV_TREE.set_pixmaps_size.
    			-- (from EV_PIXMAPABLE)
    		require -- from EV_PIXMAPABLE
    			not_destroyed: not is_destroyed
    			pixmap_not_void: a_pixmap /= Void

    	set_pointer_style (a_cursor: like pointer_style)
    			-- Assign `a_cursor' to pointer_style.
    			-- (from EV_WIDGET)
    		require -- from EV_WIDGET
    			not_destroyed: not is_destroyed
    			a_cursor_not_void: a_cursor /= Void
    		ensure -- from EV_WIDGET
    			pointer_style_assigned: pointer_style.is_equal (a_cursor)

    	swap (i: INTEGER_32)
    			-- Exchange_item at `i'-th position with item
    			-- at cursor position.
    			-- (from EV_DYNAMIC_LIST)
    		require -- from CHAIN
    			not_off: not off
    			valid_index: valid_index (i)
    		ensure -- from CHAIN
    			swapped_to_item: item = old i_th (i)
    			swapped_from_item: i_th (i) = old item

    feature -- Removal

    	frozen free_id
    			-- Free the entry associated with object_id if any
    			-- (from IDENTIFIED)
    		ensure -- from IDENTIFIED
    			object_freed: id_freed

    	prune (v: like item)
    			-- Remove `v' if present. Do not move cursor, except if
    			-- cursor was on `v', move to right neighbor.
    			-- (from EV_DYNAMIC_LIST)
    		require -- from COLLECTION
    			prunable: prunable
    		ensure then -- from SET
    			removed_count_change: old has (v) implies (vbox_count = old vbox_count - 1)
    			not_removed_no_count_change: not old has (v) implies (vbox_count = old vbox_count)
    			item_deleted: not has (v)
    		ensure then -- from EV_DYNAMIC_LIST
    			not_has_v: not has (v)
    			had_item_implies_parent_void: old has (v) implies v.parent = Void
    			had_item_implies_count_decreased: old has (v) implies vbox_count = old vbox_count - 1
    			had_item_and_was_after_implies_index_decreased: (old after and old has (v)) implies index = old index - 1

    	prune_all (v: like item)
    			-- Remove all occurrences of `v'.
    			-- (Reference or object equality,
    			-- based on object_comparison.)
    			-- Leave structure exhausted.
    			-- (from DYNAMIC_CHAIN)
    		require -- from COLLECTION
    			prunable: prunable
    		ensure -- from COLLECTION
    			no_more_occurrences: not has (v)
    		ensure then -- from DYNAMIC_CHAIN
    			is_exhausted: exhausted

    	remove
    			-- Remove current item. Move cursor to right neighbor.
    			-- (or after if no right neighbor).
    			-- (from EV_DYNAMIC_LIST)
    		require -- from ACTIVE
    			prunable: prunable
    			writable: writable
    		ensure then -- from DYNAMIC_LIST
    			after_when_empty: vbox_is_empty implies after
    		ensure then -- from EV_DYNAMIC_LIST
    			v_removed: not has (old item)
    			parent_void: (old item).parent = Void
    			count_decreased: vbox_count = old vbox_count - 1
    			index_same: index = old index

    	remove_left
    			-- Remove item to left of cursor position.
    			-- Do not move cursor.
    			-- (from EV_DYNAMIC_LIST)
    		require -- from DYNAMIC_CHAIN
    			left_exists: index > 1
    		ensure -- from DYNAMIC_CHAIN
    			new_count: vbox_count = old vbox_count - 1
    			new_index: index = old index - 1
    		ensure then -- from EV_DYNAMIC_LIST
    			left_neighbor_removed: not has (old i_th (index - 1))
    			parent_void: (old i_th (index - 1)).parent = Void
    			index_decreased: index = old index - 1

    	remove_right
    			-- Remove item to right of cursor position.
    			-- Do not move cursor.
    			-- (from EV_DYNAMIC_LIST)
    		require -- from DYNAMIC_CHAIN
    			right_exists: index < vbox_count
    		ensure -- from DYNAMIC_CHAIN
    			new_count: vbox_count = old vbox_count - 1
    			same_index: index = old index
    		ensure then -- from EV_DYNAMIC_LIST
    			right_neighbor_removed: not has (old i_th (index + 1))
    			parent_void: (old i_th (index + 1)).parent = Void
    			index_same: index = old index

    	wipe_out
    			-- Remove all items.
    			-- (from EV_DYNAMIC_LIST)
    		require -- from COLLECTION
    			prunable: prunable
    		ensure -- from COLLECTION
    			wiped_out: vbox_is_empty
    		ensure then -- from DYNAMIC_LIST
    			is_before: before

    feature -- Conversion

    	linear_representation: LINEAR [EV_WIDGET]
    			-- Representation as a linear structure
    			-- (from LINEAR)
    		require -- from  CONTAINER
    			True

    feature -- Duplication

    	copy (other: like Current)
    			-- Update current object using fields of object attached
    			-- to `other', so as to yield equal objects.
    			-- (from EV_ANY)
    		require -- from ANY
    			other_not_void: other /= Void
    			type_identity: same_type (other)
    		ensure -- from ANY
    			is_equal: is_equal (other)

    	frozen deep_copy (other: like Current)
    			-- Effect equivalent to that of:
    			--		copy (`other' . deep_twin)
    			-- (from ANY)
    		require -- from ANY
    			other_not_void: other /= Void
    		ensure -- from ANY
    			deep_equal: deep_equal (Current, other)

    	frozen deep_twin: like Current
    			-- New object structure recursively duplicated from Current.
    			-- (from ANY)
    		ensure -- from ANY
    			deep_equal: deep_equal (Current, Result)

    	frozen standard_copy (other: like Current)
    			-- Copy every field of `other' onto corresponding field
    			-- of current object.
    			-- (from ANY)
    		require -- from ANY
    			other_not_void: other /= Void
    			type_identity: same_type (other)
    		ensure -- from ANY
    			is_standard_equal: standard_is_equal (other)

    	frozen standard_twin: like Current
    			-- New object field-by-field identical to `other'.
    			-- Always uses default copying semantics.
    			-- (from ANY)
    		ensure -- from ANY
    			standard_twin_not_void: Result /= Void
    			equal: standard_equal (Result, Current)

    	frozen twin: like Current
    			-- New object equal to `Current'
    			-- twin calls copy; to change copying/twining semantics, redefine copy.
    			-- (from ANY)
    		ensure -- from ANY
    			twin_not_void: Result /= Void
    			is_equal: Result.is_equal (Current)

    feature -- Basic operations

    	frozen default: like Current
    			-- Default value of object's type
    			-- (from ANY)

    	frozen default_pointer: POINTER
    			-- Default value of type `POINTER'
    			-- (Avoid the need to write `p'.default for
    			-- some `p' of type `POINTER'.)
    			-- (from ANY)

    	default_rescue
    			-- Process exception for routines with no Rescue clause.
    			-- (Default: do nothing.)
    			-- (from ANY)

    	frozen do_nothing
    			-- Execute a null action.
    			-- (from ANY)

    	propagate_background_color
    			-- Propagate background_color recursively, to all children.
    			-- (from EV_CONTAINER)
    		require -- from EV_CONTAINER
    			not_destroyed: not is_destroyed
    		ensure -- from EV_CONTAINER
    			background_color_propagated: background_color_propagated

    	propagate_foreground_color
    			-- Propagate foreground_color recursively, to all children.
    			-- (from EV_CONTAINER)
    		require -- from EV_CONTAINER
    			not_destroyed: not is_destroyed
    		ensure -- from EV_CONTAINER
    			foreground_color_propagated: foreground_color_propagated

    	refresh_now
    			-- Force an immediate redraw of `Current'.
    			-- (from EV_WIDGET)
    		require -- from EV_WIDGET
    			not_destroyed: not is_destroyed

    feature -- Cleaning

    	reset
    			-- Reset content of Current
    			-- (from EV_ADD_REMOVE_LIST)

    feature -- Command

    	destroy
    			-- Destroy underlying native toolkit object.
    			-- Render `Current' unusable.
    			-- (from EV_ANY)
    		ensure -- from EV_ANY
    			is_destroyed: is_destroyed

    feature -- Contract support

    	is_parent_recursive (a_widget: EV_WIDGET): BOOLEAN
    			-- Is `a_widget' parent, or recursivly, parent of parent.
    			-- (from EV_CONTAINER)
    		require -- from EV_DYNAMIC_LIST
    			a_list_not_void: a_widget /= Void
    			not_destroyed: not is_destroyed
    		require -- from EV_CONTAINER
    			not_destroyed: not is_destroyed

    	may_contain (v: EV_WIDGET): BOOLEAN
    			-- May `v' be inserted in `Current'.
    			-- Instances of EV_WINDOW may not be inserted
    			-- in a container even though they are widgets.
    			-- (from EV_CONTAINER)

    	parent_of_source_allows_docking: BOOLEAN
    			-- Does parent of source to be transported
    			-- allow current to be dragged out? (See real_source)
    			-- Not all Vision2 containers are currently supported by this
    			-- mechanism, only descendents of EV_DOCKABLE_TARGET
    			-- are supported.
    			-- (from EV_DOCKABLE_SOURCE)

    	same (other: EV_ANY): BOOLEAN
    			-- Is `other' `Current'?
    			-- (from EV_DYNAMIC_LIST)

    	source_has_current_recursive (source: EV_DOCKABLE_SOURCE): BOOLEAN
    			-- Does `source' recursively contain `Current'?
    			-- As seen by parenting structure.
    			-- (from EV_DOCKABLE_SOURCE)
    		require -- from EV_DOCKABLE_SOURCE
    			not_destroyed: not is_destroyed
    			source_not_void: source /= Void

    feature -- Event handling

    	conforming_pick_actions: EV_NOTIFY_ACTION_SEQUENCE
    			-- Actions to be performed when a pebble that fits here is picked.
    			-- (from EV_PICK_AND_DROPABLE_ACTION_SEQUENCES)
    		require -- from  EV_ABSTRACT_PICK_AND_DROPABLE
    			True
    		ensure -- from EV_PICK_AND_DROPABLE_ACTION_SEQUENCES
    			not_void: Result /= Void

    	dock_ended_actions: EV_NOTIFY_ACTION_SEQUENCE
    			-- Actions to be performed after a dock completes from `Current'.
    			-- Either to a dockable target or a dockable dialog.
    			-- (from EV_DOCKABLE_SOURCE_ACTION_SEQUENCES)
    		ensure -- from EV_DOCKABLE_SOURCE_ACTION_SEQUENCES
    			not_void: Result /= Void

    	dock_started_actions: EV_NOTIFY_ACTION_SEQUENCE
    			-- Actions to be performed when a dockable source is dragged.
    			-- (from EV_DOCKABLE_SOURCE_ACTION_SEQUENCES)
    		ensure -- from EV_DOCKABLE_SOURCE_ACTION_SEQUENCES
    			not_void: Result /= Void

    	docked_actions: EV_DOCKABLE_SOURCE_ACTION_SEQUENCE
    			-- Actions to be performed when a dockable source completes a transport
    			-- Fired only if source has been moved, after parenting.
    			-- (from EV_DOCKABLE_TARGET_ACTION_SEQUENCES)
    		ensure -- from EV_DOCKABLE_TARGET_ACTION_SEQUENCES
    			not_void: Result /= Void

    	drop_actions: EV_PND_ACTION_SEQUENCE
    			-- Actions to be performed when a pebble is dropped here.
    			-- (from EV_PICK_AND_DROPABLE_ACTION_SEQUENCES)
    		require -- from  EV_ABSTRACT_PICK_AND_DROPABLE
    			True
    		ensure -- from EV_PICK_AND_DROPABLE_ACTION_SEQUENCES
    			not_void: Result /= Void

    	focus_in_actions: EV_NOTIFY_ACTION_SEQUENCE
    			-- Actions to be performed when keyboard focus is gained.
    			-- (from EV_WIDGET_ACTION_SEQUENCES)
    		ensure -- from EV_WIDGET_ACTION_SEQUENCES
    			not_void: Result /= Void

    	focus_out_actions: EV_NOTIFY_ACTION_SEQUENCE
    			-- Actions to be performed when keyboard focus is lost.
    			-- (from EV_WIDGET_ACTION_SEQUENCES)
    		ensure -- from EV_WIDGET_ACTION_SEQUENCES
    			not_void: Result /= Void

    	key_press_actions: EV_KEY_ACTION_SEQUENCE
    			-- Actions to be performed when a keyboard key is pressed.
    			-- (from EV_WIDGET_ACTION_SEQUENCES)
    		ensure -- from EV_WIDGET_ACTION_SEQUENCES
    			not_void: Result /= Void

    	key_press_string_actions: EV_KEY_STRING_ACTION_SEQUENCE
    			-- Actions to be performed when a keyboard press generates a displayable character.
    			-- (from EV_WIDGET_ACTION_SEQUENCES)
    		ensure -- from EV_WIDGET_ACTION_SEQUENCES
    			not_void: Result /= Void

    	key_release_actions: EV_KEY_ACTION_SEQUENCE
    			-- Actions to be performed when a keyboard key is released.
    			-- (from EV_WIDGET_ACTION_SEQUENCES)
    		ensure -- from EV_WIDGET_ACTION_SEQUENCES
    			not_void: Result /= Void

    	mouse_wheel_actions: EV_INTEGER_ACTION_SEQUENCE
    			-- Actions to be performed when mouse wheel is rotated.
    			-- (from EV_WIDGET_ACTION_SEQUENCES)
    		ensure -- from EV_WIDGET_ACTION_SEQUENCES
    			not_void: Result /= Void

    	pick_actions: EV_PND_START_ACTION_SEQUENCE
    			-- Actions to be performed when pebble is picked up.
    			-- (from EV_PICK_AND_DROPABLE_ACTION_SEQUENCES)
    		require -- from  EV_ABSTRACT_PICK_AND_DROPABLE
    			True
    		ensure -- from EV_PICK_AND_DROPABLE_ACTION_SEQUENCES
    			not_void: Result /= Void

    	pick_ended_actions: EV_PND_FINISHED_ACTION_SEQUENCE
    			-- Actions to be performed when a transport from `Current' ends.
    			-- If transport completed successfully, then event data
    			-- is target. If cancelled, then event data is Void.
    			-- (from EV_PICK_AND_DROPABLE_ACTION_SEQUENCES)
    		ensure -- from EV_PICK_AND_DROPABLE_ACTION_SEQUENCES
    			not_void: Result /= Void

    	pointer_button_press_actions: EV_POINTER_BUTTON_ACTION_SEQUENCE
    			-- Actions to be performed when screen pointer button is pressed.
    			-- (from EV_WIDGET_ACTION_SEQUENCES)
    		ensure -- from EV_WIDGET_ACTION_SEQUENCES
    			not_void: Result /= Void

    	pointer_button_release_actions: EV_POINTER_BUTTON_ACTION_SEQUENCE
    			-- Actions to be performed when screen pointer button is released.
    			-- (from EV_WIDGET_ACTION_SEQUENCES)
    		ensure -- from EV_WIDGET_ACTION_SEQUENCES
    			not_void: Result /= Void

    	pointer_double_press_actions: EV_POINTER_BUTTON_ACTION_SEQUENCE
    			-- Actions to be performed when screen pointer is double clicked.
    			-- (from EV_WIDGET_ACTION_SEQUENCES)
    		ensure -- from EV_WIDGET_ACTION_SEQUENCES
    			not_void: Result /= Void

    	pointer_enter_actions: EV_NOTIFY_ACTION_SEQUENCE
    			-- Actions to be performed when screen pointer enters widget.
    			-- (from EV_WIDGET_ACTION_SEQUENCES)
    		ensure -- from EV_WIDGET_ACTION_SEQUENCES
    			not_void: Result /= Void

    	pointer_leave_actions: EV_NOTIFY_ACTION_SEQUENCE
    			-- Actions to be performed when screen pointer leaves widget.
    			-- (from EV_WIDGET_ACTION_SEQUENCES)
    		ensure -- from EV_WIDGET_ACTION_SEQUENCES
    			not_void: Result /= Void

    	pointer_motion_actions: EV_POINTER_MOTION_ACTION_SEQUENCE
    			-- Actions to be performed when screen pointer moves.
    			-- (from EV_WIDGET_ACTION_SEQUENCES)
    		require -- from  EV_ABSTRACT_PICK_AND_DROPABLE
    			True
    		ensure -- from EV_WIDGET_ACTION_SEQUENCES
    			not_void: Result /= Void

    	resize_actions: EV_GEOMETRY_ACTION_SEQUENCE
    			-- Actions to be performed when size changes.
    			-- (from EV_WIDGET_ACTION_SEQUENCES)
    		ensure -- from EV_WIDGET_ACTION_SEQUENCES
    			not_void: Result /= Void

    feature -- Iteration

    	do_all (action: PROCEDURE [ANY, TUPLE [EV_WIDGET]])
    			-- Apply `action' to every item.
    			-- Semantics not guaranteed if `action' changes the structure;
    			-- in such a case, apply iterator to clone of structure instead.
    			-- (from LINEAR)
    		require -- from TRAVERSABLE
    			action_exists: action /= Void

    	do_if (action: PROCEDURE [ANY, TUPLE [EV_WIDGET]]; test: FUNCTION [ANY, TUPLE [EV_WIDGET], BOOLEAN])
    			-- Apply `action' to every item that satisfies `test'.
    			-- Semantics not guaranteed if `action' or `test' changes the structure;
    			-- in such a case, apply iterator to clone of structure instead.
    			-- (from LINEAR)
    		require -- from TRAVERSABLE
    			action_exists: action /= Void
    			test_exits: test /= Void

    	for_all (test: FUNCTION [ANY, TUPLE [EV_WIDGET], BOOLEAN]): BOOLEAN
    			-- Is `test' true for all items?
    			-- Semantics not guaranteed if `test' changes the structure;
    			-- in such a case, apply iterator to clone of structure instead.
    			-- (from LINEAR)
    		require -- from TRAVERSABLE
    			test_exits: test /= Void
    		ensure then -- from LINEAR
    			empty: vbox_is_empty implies Result

    	there_exists (test: FUNCTION [ANY, TUPLE [EV_WIDGET], BOOLEAN]): BOOLEAN
    			-- Is `test' true for at least one item?
    			-- Semantics not guaranteed if `test' changes the structure;
    			-- in such a case, apply iterator to clone of structure instead.
    			-- (from LINEAR)
    		require -- from TRAVERSABLE
    			test_exits: test /= Void

    feature -- Measurement

    	height: INTEGER_32
    			-- Vertical size in pixels.
    			-- Same as minimum_height when not displayed.
    			-- (from EV_POSITIONED)
    		require -- from EV_POSITIONED
    			not_destroyed: not is_destroyed
    		ensure -- from EV_POSITIONED
    			bridge_ok: Result = implementation.height

    	minimum_height: INTEGER_32
    			-- Lower bound on height in pixels.
    			-- (from EV_POSITIONED)
    		require -- from EV_POSITIONED
    			not_destroyed: not is_destroyed
    		ensure -- from EV_POSITIONED
    			bridge_ok: Result = implementation.minimum_height
    			positive_or_zero: Result >= 0

    	minimum_width: INTEGER_32
    			-- Lower bound on width in pixels.
    			-- (from EV_POSITIONED)
    		require -- from EV_POSITIONED
    			not_destroyed: not is_destroyed
    		ensure -- from EV_POSITIONED
    			bridge_ok: Result = implementation.minimum_width
    			positive_or_zero: Result >= 0

    	width: INTEGER_32
    			-- Horizontal size in pixels.
    			-- Same as minimum_width when not displayed.
    			-- (from EV_POSITIONED)
    		require -- from EV_POSITIONED
    			not_destroyed: not is_destroyed
    		ensure -- from EV_POSITIONED
    			bridge_ok: Result = implementation.width

    	x_position: INTEGER_32
    			-- Horizontal offset relative to parent x_position in pixels.
    			-- (from EV_POSITIONED)
    		require -- from EV_POSITIONED
    			not_destroyed: not is_destroyed
    		ensure -- from EV_POSITIONED
    			bridge_ok: Result = implementation.x_position

    	y_position: INTEGER_32
    			-- Vertical offset relative to parent y_position in pixels.
    			-- (from EV_POSITIONED)
    		require -- from EV_POSITIONED
    			not_destroyed: not is_destroyed
    		ensure -- from EV_POSITIONED
    			bridge_ok: Result = implementation.y_position

    feature -- Output

    	io: STD_FILES
    			-- Handle to standard file setup
    			-- (from ANY)

    	out: STRING_8
    			-- New string containing terse printable representation
    			-- of current object
    			-- Was declared in ANY as synonym of tagged_out.
    			-- (from ANY)

    	print (some: ANY)
    			-- Write terse external representation of `some'
    			-- on standard output.
    			-- (from ANY)

    	frozen tagged_out: STRING_8
    			-- New string containing terse printable representation
    			-- of current object
    			-- Was declared in ANY as synonym of out.
    			-- (from ANY)

    feature -- Platform

    	operating_environment: OPERATING_ENVIRONMENT
    			-- Objects available from the operating system
    			-- (from ANY)

    feature -- Setting

    	set_display_error_message (p: like display_error_message)
    			-- Set display_error_message with `p'.
    			-- (from EV_ADD_REMOVE_LIST)
    		ensure -- from EV_ADD_REMOVE_LIST
    			display_error_message_set: display_error_message = p

    	set_is_entry_valid (f: like is_entry_valid)
    			-- Set is_entry_valid with `f'.
    			-- (from EV_ADD_REMOVE_LIST)
    		ensure -- from EV_ADD_REMOVE_LIST
    			is_entry_valid_set: is_entry_valid = f

    feature -- Settings

    	set_browse_for_directory
    			-- Force directory browsing dialog to appear when user
    			-- click on `browse_button'.

    	set_browse_for_file (filter: STRING_GENERAL)
    			-- Force file browsing dialog to appear when user
    			-- click on `browse_button'.

    feature -- Status

    	count: INTEGER_32
    			-- Number of items in list?
    			-- (from EV_ADD_REMOVE_LIST)

    	is_empty: BOOLEAN
    			-- Is list empty?
    			-- (from EV_ADD_REMOVE_LIST)

    feature -- Status Report

    	is_destroyed: BOOLEAN
    			-- Is `Current' no longer usable?
    			-- (from EV_ANY)
    		ensure -- from EV_ANY
    			bridge_ok: Result = implementation.is_destroyed

    invariant
    		-- from EV_ADD_REMOVE_LIST
    	list_not_void: list /= Void
    	text_field_not_void: text_field /= Void
    	add_actions_not_void: add_actions /= Void
    	remove_actions_not_void: remove_actions /= Void
    	modify_actions_not_void: modify_actions /= Void
    	add_button_not_void: add_button /= Void
    	apply_button_not_void: apply_button /= Void
    	remove_button_not_void: remove_button /= Void

    		-- from EV_CONTAINER
    	client_width_within_bounds: is_usable implies client_width >= 0 and client_width <= width
    	client_height_within_bounds: is_usable implies client_height >= 0 and client_height <= height
    	all_radio_buttons_connected: is_usable implies all_radio_buttons_connected
    	parent_of_items_is_current: is_usable implies parent_of_items_is_current
    	items_unique: is_usable implies items_unique

    		-- from EV_WIDGET
    	pointer_position_not_void: is_usable and is_show_requested implies pointer_position /= Void
    	is_displayed_implies_show_requested: is_usable and then is_displayed implies is_show_requested
    	parent_contains_current: is_usable and then parent /= Void implies parent.has (Current)

    		-- from EV_PICK_AND_DROPABLE
    	user_interface_modes_mutually_exclusive: mode_is_pick_and_drop.to_integer + mode_is_drag_and_drop.to_integer + mode_is_target_menu.to_integer = 1

    		-- from EV_ANY
    	is_initialized: is_initialized
    	is_coupled: implementation /= Void and then implementation.interface = Current
    	default_create_called: default_create_called

    		-- from ANY
    	reflexive_equality: standard_is_equal (Current)
    	reflexive_conformance: conforms_to (Current)

    		-- from EV_DOCKABLE_SOURCE
    	parent_permits_docking: is_dockable implies parent_of_source_allows_docking

    		-- from EV_COLORIZABLE
    	background_color_not_void: is_usable implies background_color /= Void
    	foreground_color_not_void: is_usable implies foreground_color /= Void

    		-- from EV_POSITIONED
    	width_not_negative: is_usable implies width >= 0
    	height_not_negative: is_usable implies height >= 0
    	minimum_width_not_negative: is_usable implies minimum_width >= 0
    	minimum_height_not_negative: is_usable implies minimum_height >= 0

    		-- from LIST
    	before_definition: before = (index = 0)
    	after_definition: after = (index = vbox_count + 1)

    		-- from CHAIN
    	non_negative_index: index >= 0
    	index_small_enough: index <= vbox_count + 1
    	off_definition: off = ((index = 0) or (index = vbox_count + 1))
    	isfirst_definition: isfirst = ((not vbox_is_empty) and (index = 1))
    	islast_definition: islast = ((not vbox_is_empty) and (index = vbox_count))
    	item_corresponds_to_index: (not off) implies (item = i_th (index))
    	index_set_has_same_count: index_set.count = vbox_count

    		-- from ACTIVE
    	writable_constraint: writable implies readable
    	empty_constraint: vbox_is_empty implies (not readable) and (not writable)

    		-- from INDEXABLE
    	index_set_not_void: index_set /= Void

    		-- from BILINEAR
    	not_both: not (after and before)
    	before_constraint: before implies off

    		-- from LINEAR
    	after_constraint: after implies off

    		-- from TRAVERSABLE
    	empty_constraint: vbox_is_empty implies off

    		-- from FINITE
    	empty_definition: vbox_is_empty = (vbox_count = 0)
    	non_negative_count: vbox_count >= 0

    		-- from DYNAMIC_CHAIN
    	extendible: extendible

    indexing
    	copyright: "Copyright (c) 1984-2006, Eiffel Software and others"
    	license: "Eiffel Forum License v2 (see http://www.eiffel.com/licensing/forum.txt)"
    	source: "[
    		Eiffel Software
    		356 Storke Road, Goleta, CA 93117 USA
    		Telephone 805-685-1006, Fax 805-685-6869
    		Website http://www.eiffel.com
    		Customer support http://support.eiffel.com
    	]"

    end -- class EV_ADD_REMOVE_PATH_LIST