in F12 alpha 1, launching gnome-appearance-properties, either from the command line or when right-clicking and selecting 'Change Desktop Background', terminates in a segfault after a couple of seconds. This happens every time.

the cause and bt is: 

Program terminated with signal 11, Segmentation fault.
#0  gnome_bg_set_color (bg=0x9337f80, type=GNOME_BG_COLOR_SOLID, primary=0x0, 
    secondary=0x0) at gnome-bg.c:511
511			bg->primary = *primary;

(gdb) bt
#0  gnome_bg_set_color (bg=0x9337f80, type=GNOME_BG_COLOR_SOLID, primary=0x0, 
    secondary=0x0) at gnome-bg.c:511
#1  0x0805fcfe in set_bg_properties (item=0x9492470) at gnome-wp-item.c:73
#2  0x080603c6 in gnome_wp_item_new (filename=0x8070ac2 "(none)", 
    wallpapers=0x91796f0, thumbnails=0x9120140) at gnome-wp-item.c:143
#3  0x080560ea in wp_load_stuffs (user_data=0x90fdc80)
    at appearance-desktop.c:946
#4  0x00a19292 in g_idle_dispatch (source=0x921ef50, callback=0, 
    user_data=0x90fdc80) at gmain.c:4065
#5  0x00a1b0a8 in g_main_dispatch (context=<value optimized out>)
    at gmain.c:1960
#6  IA__g_main_context_dispatch (context=<value optimized out>) at gmain.c:2513
#7  0x00a1e9d8 in g_main_context_iterate (context=0x905fd08, 
    block=<value optimized out>, dispatch=1, self=0x90340f8) at gmain.c:2591
#8  0x00a1ee4f in IA__g_main_loop_run (loop=0x9037608) at gmain.c:2799
#9  0x032f6dd9 in IA__gtk_main () at gtkmain.c:1205
#10 0x080594a9 in main (argc=1, argv=0xbf9e4fd4) at appearance-main.c:210
 
I have a couple of core files, but they're 33m and I'm at home, so let me know if anyone needs them.