It would be great to know what message caused this hang: BROWSER ----------------------------------------------------------------------------------- 0 NtWaitForMultipleObjects 1 WaitForMultipleObjectsEx 2 uxtheme.dll: offset=0x1980 function=unknown 3 uxtheme.dll: offset=0x196f function=unknown 4 InternalFindAtom 5 `anonymous namespace'::ProcessOrDeferMessage(HWND__ *,unsigned int,unsigned __int64,__int64) src 6 NeuteredWindowProc(HWND__ *,unsigned int,unsigned __int64,__int64) src 7 DispatchMessageW 8 DispatchHookA 9 rlls64.dll: offset=0x6056b function=unknown 10 NtdllHkINLPCWPRETSTRUCT_W 11 CallHookWithSEH 12 _fnHkINLPMSG 13 _fnDWORD 14 CallNextHookEx 15 rlls64.dll: offset=0x6056b function=unknown 16 NtdllHkINLPCWPRETSTRUCT_W 17 MsgWaitForMultipleObjects 18 PR_Unlock src 19 mozilla::ipc::MessageChannel::WaitForSyncNotify() src 20 mozilla::ipc::MessageChannel::Send(IPC::Message *,IPC::Message *) src 21 mozilla::jsipc::PJavaScriptParent::SendGet(unsigned __int64 const &,mozilla::jsipc::ObjectVariant const &,mozilla::jsipc::JSIDVariant const &,mozilla::jsipc::ReturnStatus *,mozilla::jsipc::JSVariant *) src 22 mozilla::jsipc::JavaScriptBase<mozilla::jsipc::PJavaScriptParent>::SendGet(mozilla::jsipc::ObjectId const &,mozilla::jsipc::ObjectVariant const &,mozilla::jsipc::JSIDVariant const &,mozilla::jsipc::ReturnStatus *,mozilla::jsipc::JSVariant *) src 23 mozilla::jsipc::WrapperOwner::get(JSContext *,JS::Handle<JSObject *>,JS::Handle<JSObject *>,JS::Handle<jsid>,JS::MutableHandle<JS::Value>) src 24 CPOWProxyHandler::get(JSContext *,JS::Handle<JSObject *>,JS::Handle<JSObject *>,JS::Handle<jsid>,JS::MutableHandle<JS::Value>) src 25 js::Proxy::get(JSContext *,JS::Handle<JSObject *>,JS::Handle<JSObject *>,JS::Handle<jsid>,JS::MutableHandle<JS::Value>) src 26 js::DirectProxyHandler::get(JSContext *,JS::Handle<JSObject *>,JS::Handle<JSObject *>,JS::Handle<jsid>,JS::MutableHandle<JS::Value>) src 27 js::Proxy::get(JSContext *,JS::Handle<JSObject *>,JS::Handle<JSObject *>,JS::Handle<jsid>,JS::MutableHandle<JS::Value>) src 28 js::GetProperty(JSContext *,JS::Handle<JSObject *>,JS::Handle<JSObject *>,JS::Handle<jsid>,JS::MutableHandle<JS::Value>) src 29 js::jit::ComputeGetPropResult src 30 js::jit::DoGetPropFallback src 31 unknown: offset=unknown function=unknown

Can you get the message ID from the parameter in ProcessOrDeferMessage?

(In reply to Benjamin Smedberg [:bsmedberg] from comment #1) > Can you get the message ID from the parameter in ProcessOrDeferMessage? Hmm, might be in the dump files? I'll take a look, thanks.