diff -u -r1.649 xfns.c
--- src/xfns.c	8 Dec 2005 15:48:56 -0000	1.649
+++ src/xfns.c	26 Dec 2005 20:50:33 -0000
@@ -3265,8 +3265,6 @@
   x_default_parameter (f, parms, Qfullscreen, Qnil,
                        "fullscreen", "Fullscreen", RES_TYPE_SYMBOL);
 
-  f->output_data.x->parent_desc = FRAME_X_DISPLAY_INFO (f)->root_window;
-
   /* Compute the size of the X window.  */
   window_prompting = x_figure_window_size (f, parms, 1);