I\'ll be coding along in Visual Studio 2008, and eventually I make a mistake. I press CTRL - Z to undo and NOTHING HAPPENS. I\'m not talking about anything
I just had this problem of Undo becoming disabled. I'm using VS2008 Developer Edition. I don't have ReSharper intsalled. Going off @Joseph's suggestion I thought I'd check the clipboard, but before I did that I tried cycling the clipboard Edit -> Cycle Clipboard Ring
and Undo came back. This is the first time it has happened. I will update this if it happens again.
Update Seems I got lucky. It happened again and the Edit->Cycle Clipboard Ring
trick didn't work. This has never happened to me before, and the situation it is occurring in is novel too - I'm running two instances of VS2008 - one with a WCF service running, the other a simple web app calling the webservice. The really odd thing is, is that when I am actually debugging the undo icon becomes active! As soon as I stop debugging it greys out (in both instances)
I've come across the same issue - and I too use VisualSVN and ReShaper. What version of ReSharper are you using, 4.5.x?
I've found it appearing with 4.5.x but a recent EAP build (I can't recall which) did address it for me after I reset the Keyboard layout in Visual Studio.
So first as others have stated, try disabling ReSharper (Addin Manager, until startup too) restart (the IDE) and see if it appears whilst your working (after resetting the keyboard layout).