The changes to enforce single handling of all key events were breaking
custom-alt-tab keypress handlers, since that code was assuming that
key event would get to process_tab_grab(), and then maybe to
process_event() and then to the plugin's xevent_filter to detect a
key release.
We centeralize all of this handling into process_tab_grab() and either
- Invoke a custom handler for the key press
- Select the current window on modifier release by calling a new
pseudo-binding "tab_popup_select"
- Cancel the grab on an unbound key by calling a new pseudo-binding
"tab_popup_cancel"
http://bugzilla.gnome.org/show_bug.cgi?id=590754