When a task is DONE, you get to the Congratulation screen. there is no way to undo if puttin the task in DONE was a mistake
FYI you can go back to the task screen and hit command + z to undo, and you’ll get that task back in your list :)
I’ve done Cmd+Opt+Return many times when I’ve meant to make Slash full screen. Would be nice to Undo then.
Better yet, have a keyboard shortcut to make Slash full screen, like 1) Cmd+Tab to switch to Slash app and then 2) Cmd+Opt+Space to get to Full Screen.