Undoing and redoing an operation
You can undo and redo each change that has been applied to the canvas. For example, you can undo the removal of blocks, undo changed parameter values, or undo the rerouting of a wire.
It is not possible to undo/redo the change to a model name or its description.
Note:
To use the key combinations mentioned below, the canvas must have the focus. When the documentation pane or the palette currently has the focus, the change on the canvas is not undone/redone.
To undo or redo an operation
To undo the last operation, click 
in the toolbar of the model editor. Or press Ctrl+Z.
To redo the last operation, click 
in the toolbar of the model editor. Or press Ctrl+Y.
The above toolbar buttons are only enabled when there is an operation that can be undone or redone.