Description of problem:
My VPN connection died, while Thunderbird was probably working on something. When I tried to close it, it seemed to enter an infinite loop. gdb:
(gdb) l
528		while(1)
529		{
530			PendingRequest *req = dpy->xcb->pending_requests;
531			xcb_generic_reply_t *response;
532	
533			if(req != current && req->reply_waiter)
534			{
535				ConditionWait(dpy, dpy->xcb->reply_notify);
536				/* Another thread got this reply. */
537				continue;
(gdb) bt
#0  _XReply (dpy=0x7f9d0c354000, rep=0x7fff240df2e0, extra=0, discard=0) at xcb_io.c:533
#1  0x00000037b3a32058 in XListExtensions (dpy=0x7f9d0c354000, nextensions=0x7fff240df338) at ListExt.c:47
#2  0x000000000044b21e in X11Error (display=0x7f9d0c354000, event=0x7fff240dfc60) at nsX11ErrorHandler.cpp:85
#3  0x00000037b3a4810f in _XError (dpy=0x7f9d0c354000, rep=<optimized out>) at XlibInt.c:1583
#4  0x00000037b3a44f91 in handle_error (dpy=0x7f9d0c354000, err=0x7f9cc7c1e040, in_XReply=<optimized out>) at xcb_io.c:166
#5  0x00000037b3a44fd5 in handle_response (dpy=0x7f9d0c354000, response=0x7f9cc7c1e040, in_XReply=<optimized out>) at xcb_io.c:266
#6  0x00000037b3a45de0 in _XReply (dpy=0x7f9d0c354000, rep=0x7fff240dfe10, extra=0, discard=1) at xcb_io.c:566
#7  0x00000037b3a415a3 in XSync (dpy=0x7f9d0c354000, discard=1) at Sync.c:44
#8  0x00000037b3a1ffa0 in XCloseDisplay (dpy=0x7f9d0c354000) at ClDisplay.c:61
#9  0x00000037bd652d48 in gdk_display_x11_finalize (object=0x7f9d0c361190 [GdkDisplayX11]) at gdkdisplay-x11.c:890
#10 0x00000037b220f6c1 in g_object_unref (_object=0x7f9d0c361190) at gobject.c:2734
#11 0x00000000004425c0 in MOZ_gdk_display_close (display=0x7f9d0c361190 [GdkDisplayX11]) at nsAppRunner.cpp:2605
#12 0x00000000004474ee in XRE_main (argc=<optimized out>, argv=<optimized out>, aAppData=<optimized out>) at nsAppRunner.cpp:3603
#13 0x00000000004421fc in main (argc=1, argv=0x7fff240e0818) at nsMailApp.cpp:104


Version-Release number of selected component (if applicable):
thunderbird-3.1.10-1.fc15.x86_64

How reproducible:
Happened several times.

Steps to Reproduce:
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Actual results:


Expected results:


Additional info: