Undo, Redo, Select All
The Undo (Ctrl+Z) command 
enables you to undo an editing change. An unlimited number of Undo actions is supported. Every action can be undone and it is possible to undo one command after another till the first action that was made since the document was opened.
The Redo (Ctrl+Y) command 
allows you to redo any number of previously undone commands. By using the Undo and Redo commands, you can step backward and forward through the history of commands.
The Select All command selects the entire contents of the Design Document window.