Only a 'close' button in Edit window, no 'Cancel' / 'Save' pair

When you open the Edit window for a card, you can only get out of it by clicking on ‘Close’. There is no ‘Cancel’, and there is no feedback that something was changed. How are users supposed to recover the original card if they mess up the editing and don’t want to save it?

Ctrl+z can be used inside a field to undo simple changes, and the Edit>Undo menu option in the main window can also be used to revert a note to its previous state.

That’s not entirely true - changes made with the keyboard will cause the displayed text on the screen to update.