This has happened repeatedly… I am editing text. Then hit Command-Z to undo something. The whole window becomes neutral gray and I cannot see the elements on the page any more. They are technically there, because if I save the project then relaunch, things pop up again. But i have to be sure to save immediately and relaunch.
Weird nonetheless.
On a similar note, it sure would be nice to have autosave options in preferences (auto-save never, or autosave every XX minutes). I have lost work more than once.
I have also encountered this behaviour… and the same relaunch ‘solution’.
One thing I have noticed with Command-Z undos is that they don’t work within the text-editor — but strangely they do work if you click out of the text-editor and then select the outline of the text before hitting the Command-Z undos.