Comment 22 for bug 43464

I just went through Rhythmbox's changelog looking for clues and found this entry:

2007-02-02 Jonathan Matthew <email address hidden>

    * configure.ac:
    * data/rhythmbox.schemas:
    * plugins/Makefile.am:
    * plugins/mmkeys/Makefile.am:
    * plugins/mmkeys/mmkeys.rb-plugin.desktop.in:
    * plugins/mmkeys/rb-mmkeys-plugin.c: (rb_mmkeys_plugin_init),
    (media_player_key_pressed), (window_focus_cb), (grab_mmkey),
    (ungrab_mmkey), (filter_mmkeys), (mmkeys_grab), (impl_activate),
    (impl_deactivate), (rb_mmkeys_plugin_class_init):
    New plugin for media player key shortcuts. Handles both dbus signals
    from gnome-settings-daemon and the older XGrabKey method (bug #398184).

    * shell/rb-shell-player.c: (rb_shell_player_init):
    Remove XGrabKey key shortcut handling code.

The Gnome Bugzilla bug that this patch addresses has some more details in the comments:
    http://bugzilla.gnome.org/show_bug.cgi?id=398184