The program recognizes the 'Z' symbol being made with the mouse. You must however move the mouse quickly enough for the shape to be recognized. In the options menu you can assign and change recognition parameters.
Of course you may restore the windows by using hotkeys:
Ctrl + Alt + Home
Or right click on the tray icon , call popup menu and select 'Restore all' item.
Zigzag Cleaner Plus allows you to configure the command with the symbol you want.