When shortcut keys are inconsistent in multiple configurations

e.g. Alt+X is a shortcut key in configuration A only. Select multiple configurations (including A) and open their Keyboard properties. Press Alt+X in "Press New Shortcut Key" field. ** "Currently Assigned to" shows "[Undefined]". Suggestion: "Currently Assigned to" should show "[*]" or something. Also, should show some symbol in "Current Keys" list in such cases.