I am using WF4. There is in fact an UNDO/REDO buttun pair. But they are rarely if ever lit up to be used. The conditions for thier use are very restricted. About the only time they work is during sketching. Example. In drawing mode, make a mistake... click the wrong button or something... no Undo. Whatever you did wrong needs to be redone. Sorry, this is a rant, I know. But it IS rather annoying. In most programs, you can back up several steps and start over if you find you've made an error, or simply don't like the way something is turning out.
Chris Benner
Autodesk ® Expert Elite