While trying to search in Mail.app, I somehow seem to have selected all Mail in one inbox and flagged them all (as important). Somehow a matter of two keystrokes.
How can I undo that? I want to remove the flags from all the Mail that didn't have flags 1 minute ago, without removing flags from the Mail that was actually flagged previously.
Clicking "Edit" in the menu bar shows that the Undo action is greyed out. I tried cmd-z anyway but it didn't do anything.