When a zip file is accessed as if it was a directory (which is a great feature), pressing F3 works in showing the preview of the compressed files. However, opening a xml file causes the ESC key not to work, so that one cannot go back anymore (it is likely overridden by the XML viewer). Also, pressing F4 to edit files seems to work, but then the changes are not persistent.
edit: also ctrl+f doen’t work, so no hotkey is going to work with F3 xml preview I am afraid.