All the hotkeys grabbed by xfce4-power-manager (Battery and Brightness) are not processed when the num lock is turned on. When turning numlock off everything works as expected.
having the same problem on a samsung R580. hotkeys works when numlock is off but not when turned on. While running xev, keycodes does not bubble to xev when numlock is off (i think they where trapped by power-manager) but when numlock is on, xev display hotkeys keycodes : XF86MonBrightnessDown sample with numlock off (keycode does not bubble, power-manager modify brightness) : FocusOut event, serial 33, synthetic NO, window 0x4800001, mode NotifyGrab, detail NotifyAncestor FocusIn event, serial 33, synthetic NO, window 0x4800001, mode NotifyUngrab, detail NotifyAncestor KeymapNotify event, serial 33, synthetic NO, window 0x0, keys: 51 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 with numlock on (keycode bubble, power-manager does nothing) : KeyPress event, serial 33, synthetic NO, window 0x4800001, root 0x15d, subw 0x0, time 15864343, (352,199), root:(946,515), state 0x10, keycode 232 (keysym 0x1008ff03, XF86MonBrightnessDown), same_screen YES, XLookupString gives 0 bytes: XmbLookupString gives 0 bytes: XFilterEvent returns: False KeyRelease event, serial 33, synthetic NO, window 0x4800001, root 0x15d, subw 0x0, time 15864344, (352,199), root:(946,515), state 0x10, keycode 232 (keysym 0x1008ff03, XF86MonBrightnessDown), same_screen YES, XLookupString gives 0 bytes: XFilterEvent returns: False
dupe of bug 6549
*** This bug has been marked as a duplicate of bug 6549 ***