I did check that, and I haven’t changed it. This seems to happen at random, sometimes after working for a bit but I usually see it
very quickly. I see it very often while working in 2.5D where I would expect to have a hell of a lot of undo’s. The only fix is to kill
off ZBrush and start it back up and that works most of the time but not all.
The key thing here is that I can use undo if I click on the button in the Edit Menu, but not by using Control Z, and that is why
I think its a bug of some sort.
Does that make sense?
Cheers,
Mealea