Description of problem:
Whenever I run either mplayer or glxgears, metacity crashes and makes use of the desktop rather difficult (for my wife and children; I can switch via Ctrl-Alt-F2 to console and kill the offending program, but still even I cannot use mplayer). Considering we use the computer in question as a media center, it is a bit of problem.

Version-Release number of selected component (if applicable):
metacity-2.28.0-23.el6.i686
gnome-session-2.28.0-22.el6.i686
xorg-x11-drv-ati-7.5.99-3.el6.i686
kernel-2.6.32-573.22.1.el6.i686

How reproducible:
100% (at least ten out of ten, but probably more)

Steps to Reproduce:
1.login to Gnome session with metacity as the window manager
2.run mplayer
3.

Actual results:
mplayer (in default configuration) or any GL application (tested with mplayer -vo gl and with glxgears) make a picture in root window BELOW all other windows and Alt-TAB or other means are not available. I have to do Ctrl-Alt-F2 to kill from ckonsole.

Expected results:
just works, pressing 'f' in mplayer switches to the full screen and back

Additional info:

Traceback is

Loaded symbols for /usr/lib/libdbus-glib-1.so.2.1.0
Reading symbols from /usr/lib/gconv/ISO8859-1.so...Reading symbols from /usr/lib/debug/usr/lib/gconv/ISO8859-1.so.debug...done.
done.
Loaded symbols for /usr/lib/gconv/ISO8859-1.so
Core was generated by `metacity --replace'.
Program terminated with signal 6, Aborted.
#0  0x00cc9424 in __kernel_vsyscall ()
(gdb) t a a bt

Thread 1 (Thread 0xb76e8870 (LWP 4736)):
#0  0x00cc9424 in __kernel_vsyscall ()
#1  0x00250871 in raise (sig=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:64
#2  0x0025214a in abort () at abort.c:92
#3  0x004b8554 in g_assertion_message (domain=0x80b2417 "metacity", 
    file=0x80bdc07 "ui/ui.c", line=597, 
    func=0x80bdc80 "meta_ui_get_default_window_icon", 
    message=<value optimized out>) at gtestutils.c:1358
#4  0x004b8b0e in g_assertion_message_expr (domain=0x80b2417 "metacity", 
    file=0x80bdc07 "ui/ui.c", line=597, 
    func=0x80bdc80 "meta_ui_get_default_window_icon", 
    expr=0x80bdbfa "default_icon") at gtestutils.c:1369
#5  0x080a9cb0 in meta_ui_get_default_window_icon (ui=0x98829c8) at ui/ui.c:597
#6  0x0806c936 in get_fallback_icons (screen=0x9883238, xwindow=69206017, 
    icon_cache=0x98b2ba4, wm_hints_pixmap=0, wm_hints_mask=0, 
    iconp=0xbfb5f08c, ideal_width=32, ideal_height=32, mini_iconp=0xbfb5f088, 
    ideal_mini_width=16, ideal_mini_height=16) at core/iconcache.c:45
#7  meta_read_icons (screen=0x9883238, xwindow=69206017, icon_cache=0x98b2ba4, 
    wm_hints_pixmap=0, wm_hints_mask=0, iconp=0xbfb5f08c, ideal_width=32, 
    ideal_height=32, mini_iconp=0xbfb5f088, ideal_mini_width=16, 
    ideal_mini_height=16) at core/iconcache.c:824
#8  0x080845be in meta_window_update_icon_now (window=0x98b2b70)
    at core/window.c:5862
#9  0x0808bca8 in meta_window_new_with_attrs (display=0x987cb00, 
    xwindow=69206017, must_be_viewable=1, attrs=0x98b018c) at core/window.c:604
#10 0x08077ced in meta_screen_manage_all_windows (screen=0x9883238)
    at core/screen.c:766
#11 0x0806303a in meta_display_open () at core/display.c:739
#12 0x080714cb in main (argc=1, argv=0xbfb5faa4) at core/main.c:621
(gdb)