[Pharo-project] Undo after Cancel

I have some minor problem with Pharo images: after precssing Alt+l (Cancel) in workspace, all text loss without possibility to recovery. Undo not work in that case and give to raise debugger window sometimes. And another newbie question. How to disable or change hotkey action? Changing options in preference browser section "keyboard" do not any effects for my. I am working with latest Pharo images in Windows XP SP2. Alexander