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EiffelStudio

# History

EiffelBuild has an limitless undo/redo mechanism built in. However, this mechanism only applies to the structure of the objects you are developing in your project.

For example, every time you create, reparent or delete an object in your project, this is recorded in the history. If you modify properties of an object (Using an object editor), these modifications are not recorded in the history.

## Undo

To undo a change, click on the main toolbar You can repeatedly undo, until you get to the beginning of the history, at which point, this button is disabled.

## Redo

To redo a change (only applicable after one ore more undo's), click on the main toolbar. You can repeatedly redo, until the history becomes current again, and at which point, this button is disabled.

## History window

The screenshot above shows the appearance of the history window.

This visibility of the window may be toggled by clicking on the main toolbar. You may also select History from the View menu to show the history window, and click the Close button to close the window manually.

Looking at the screenshot above, you will see that the last action in the history list is selected. This is always the case while working, until you start undoing your changes. To go back six steps, so that (in this case), there is just the one BUTTON added to the HORIZONTAL_BOX, you could click the undo button on the main toolbar six times, or you can simply select the third item in this list. both have the same effect. You can also redo by selecting an item below the currently selection in the history list (Only possible after an undo).

If you execute an action which will be added to the history while the history is not at the final position, all history events after this current position will be removed, and the history will be up to date again.

Note: If you use the history list to move through many recorded actions at once, there may be a slight delay dependent on the systems complexity and steps moved.

See also
Builder window
Layout constructor