[moniker]

Aha! I was finally able to reproduce. I've gotten a few error messages, some about an invalid index into an NSArray but also the NSUndoManager ones. They just started appearing again.

One of the NSUndoManager alerts popped up and I stopped what I was doing to see what I could do to make it happen again. If I do the 2 finger scroll gesture, another alert pops up. Basically, I can make as many pop up as I want simply by making that gesture once one fires. If I get rid of them all and then immediately make that gesture again, it will pop up. If instead I click around and scroll using the scroll bars, they don't pop up anymore. I'm not sure what initially triggers them, but hopefully these extra details will help.