Undoing and Redoing Actions on Objects
The undo mechanism in a drawing or in the navigator allows you to cancel the last action carried out. Having canceled an action you can subsequently change your mind and redo it.
This is true:
• for purely graphical operations,
• for those involving actions on the repository (creating or deleting objects for example).
Having created an object in a diagram, if you decide to undo this creation action, the object will be deleted from both the diagram and the repository. The same applies when you redo an action that you canceled.
To cancel the last action carried out in a diagram or in the navigator:
In the desktop toolbar, click Undo 
.To redo an action you canceled in a diagram or in the navigator:
In the desktop toolbar, click Redo 
.You can also undo or redo one or several actions carried out in your private workspace: object creation and deletion, modification of object properties, etc.
To undo one or several actions:
1. In the desktop toolbar, click button Undo .
.The window that appears shows the list of actions that you can cancel.
2. Move the cursor in the window to select the (successive) actions you want to undo, then click to undo these actions.
You can only undo actions chronologically.
To undo only the last action carried out, simply click Undo.To redo one or several canceled actions:
Proceed in the same way as before, having clicked the drop-down list arrow of the Redo button .To only redo the last action carried out, simply click Redo.