(gdb) backtrace #0 0x0837b000 in shade () #1 0x00b20d64 in clearlooks_rc_style_register_type () from /usr/lib/gtk-2.0/2.4.0/engines/libclearlooks.so #2 0x003bcedf in gtk_rc_scanner_new () from /usr/lib/libgtk-x11-2.0.so.0 #3 0x003bd366 in gtk_rc_get_style () from /usr/lib/libgtk-x11-2.0.so.0 #4 0x00469c38 in gtk_widget_reset_shapes () from /usr/lib/libgtk-x11-2.0.so.0 #5 0x003cee73 in gtk_size_group_remove_widget () from /usr/lib/libgtk-x11-2.0.so.0 #6 0x003cf191 in gtk_size_group_remove_widget () from /usr/lib/libgtk-x11-2.0.so.0 #7 0x004642a4 in gtk_widget_size_request () from /usr/lib/libgtk-x11-2.0.so.0 #8 0x00474eba in gtk_window_move () from /usr/lib/libgtk-x11-2.0.so.0 #9 0x00475dca in gtk_window_get_position () from /usr/lib/libgtk-x11-2.0.so.0 #10 0x0047bc91 in gtk_plug_get_id () from /usr/lib/libgtk-x11-2.0.so.0 #11 0x005be7e7 in g_cclosure_marshal_VOID__VOID () from /usr/lib/libgobject-2.0.so.0 #12 0x005b2d9b in g_cclosure_new_swap () from /usr/lib/libgobject-2.0.so.0 #13 0x005b3285 in g_closure_invoke () from /usr/lib/libgobject-2.0.so.0 #14 0x005c13b0 in g_signal_stop_emission () from /usr/lib/libgobject-2.0.so.0 #15 0x005c2eb0 in g_signal_emit_valist () from /usr/lib/libgobject-2.0.so.0 #16 0x005c3223 in g_signal_emit () from /usr/lib/libgobject-2.0.so.0 #17 0x0046466d in gtk_widget_show () from /usr/lib/libgtk-x11-2.0.so.0 #18 0x003086f4 in gtk_container_get_focus_hadjustment () #19 0x00463a87 in gtk_widget_show_all () from /usr/lib/libgtk-x11-2.0.so.0 #20 0x084140f7 in create_plugged_main_menu () #21 0x0841606b in realmain_ () #22 0x0807dcc7 in MAIN__ () #23 0x08502026 in main (qq ) Solutions: clearlooks gtk theme error change to a new theme with gnome-control-center (Other section > Theme icon) like Redhat one Given by dries