Ctrl+Alt+J is bound to start jEdit when it is installed (which was pretty surprise by itself and was discovered accidentally). I need this combination for another program, so I went to "Start jEdit" shortcut's properties and reset the "Shortcut key" property to a blank value.
However, the hotkey still remains bound to starting jEdit (which happens when I press the keys), although the property of a shortcut is displayed as a blank value.

How can I get rid of it?