Undo [webOS 2.0.1+] 10
This tip is only for devices running webOS 2.0.1 and higher
Although Undo has still not been added to the Application Edit dropdown menus since we originally reported on it, the ability to undo is available for anyone on webOS 2.0.1 or above that knows how to do a meta tap. By holding down the gesture area and pressing Z on the keyboard, you can undo a number of different text-related actions, such as typing (anywhere from one character to a whole paragraph or more), triggering autocorrect, pasting, deleting, etc., and it appears to work throughout most of the OS. So, no more accidently losing one of your memos or a well thought out email, because Undo is here and will even allow you to undo multiple sets of actions.
In case you're wondering, meta tap + y will not give you redo, as it does on a desktop computer. Hopefully that functionality will be added in the future.