after hitting Enter to edit a file name in a contact sheet, one should be able to hit ctrl-z to undo accidental deletion of the file name (or accidental butchering of file name). Also, ctrl-backspace is expected by many users to delete previous "word" (separated by text separators, be they spaces or periods or whatever), ctrl-shift-arrow is expected to select the same, and so on. At present, ctrl-arrow closes the editing box; ctrl-backspace inserts odd characters.