--- modules/video_output/x11/xcommon.c.orig	2006-10-15 21:16:55.185236207 +0200
+++ modules/video_output/x11/xcommon.c	2006-10-15 21:17:44.335193511 +0200
@@ -886,8 +886,10 @@
         vlc_value_t val;
 
         /* Update the object variable and trigger callback */
+        vlc_mutex_unlock( &p_vout->p_sys->lock );
         val.b_bool = !p_vout->b_fullscreen;
         var_Set( p_vout, "fullscreen", val );
+        vlc_mutex_lock( &p_vout->p_sys->lock );
 
         ToggleFullScreen( p_vout );
         p_vout->i_changes &= ~VOUT_FULLSCREEN_CHANGE;