Undo and versions

⌘Z undoes and ⇧⌘Z redoes, including a delete straight after it happened.

Undo does not survive a reload, so deleting screens with the keyboard also saves a version of the board, at most every two minutes. Open Version history in the flow menu to see them and put a board back.

A board keeps sixty versions; the automatic ones go first. Restoring saves the board as it was before, so a restore can itself be undone, and comments are never touched by either.