MIDI Designer provides a single-level undo. That means that either all changes are rolled back or no changes at all.*
Access it by hitting the undo icon here:
which brings up this dialog:
- Pressing YES will roll back all changes done in Design Mode
- Pressing COMMIT CHANGES means that any subsequent Undo will only go back to this point.
- Pressing Cancel returns you to editing (like never pressing Undo at all)
*Unlike a multi-level undo, you can't step backwards and forwards through your changes. While multi-level undo is advantageous in many cases, it can also be confusing, especially when change sets overlap.