r99404 Reproducibility: often Steps: Perform a search for anything in Google. What happened: Assert failure. ASSERTION FAILED: !m_activeIteratorCount /Users/rex/WebKit/Source/WebCore/dom/EventListenerMap.cpp(180) : EventListenerVector *WebCore::EventListenerMap::find(const WTF::AtomicString &) 1 0x10d9e846e WebCore::EventListenerMap::find(WTF::AtomicString const&) 2 0x10d9f416a WebCore::EventTarget::fireEventListeners(WebCore::Event*) 3 0x10e98e2c9 WebCore::WindowEventContext::handleLocalEvents(WebCore::Event*) 4 0x10d9ccc3d WebCore::EventDispatcher::dispatchEvent(WTF::PassRefPtr<WebCore::Event>) 5 0x10e3580a4 WebCore::MouseEventDispatchMediator::dispatchEvent(WebCore::EventDispatcher*) const 6 0x10d9cc225 WebCore::EventDispatcher::dispatchEvent(WebCore::Node*, WTF::PassRefPtr<WebCore::EventDispatchMediator>) 7 0x10e379ddf WebCore::Node::dispatchMouseEvent(WebCore::PlatformMouseEvent const&, WTF::AtomicString const&, int, WebCore::Node*) 8 0x10d9d90ff WebCore::EventHandler::updateMouseEventTargetNode(WebCore::Node*, WebCore::PlatformMouseEvent const&, bool) 9 0x10d9d713c WebCore::EventHandler::dispatchMouseEvent(WTF::AtomicString const&, WebCore::Node*, bool, int, WebCore::PlatformMouseEvent const&, bool) 10 0x10d9d86ca WebCore::EventHandler::handleMouseMoveEvent(WebCore::PlatformMouseEvent const&, WebCore::HitTestResult*) 11 0x10d9d7cf6 WebCore::EventHandler::mouseMoved(WebCore::PlatformMouseEvent const&) 12 0x10bcce561 _ZN6WebKitL16handleMouseEventERKNS_13WebMouseEventEPN7WebCore4PageE 13 0x10bcce3ab WebKit::WebPage::mouseEvent(WebKit::WebMouseEvent const&) 14 0x10bddf637 void CoreIPC::callMemberFunction<WebKit::WebPage, void (WebKit::WebPage::*)(WebKit::WebMouseEvent const&), WebKit::WebMouseEvent>(CoreIPC::Arguments1<WebKit::WebMouseEvent> const&, WebKit::WebPage*, void (WebKit::WebPage::*)(WebKit::WebMouseEvent const&)) 15 0x10bdd46f6 void CoreIPC::handleMessage<Messages::WebPage::MouseEvent, WebKit::WebPage, void (WebKit::WebPage::*)(WebKit::WebMouseEvent const&)>(CoreIPC::ArgumentDecoder*, WebKit::WebPage*, void (WebKit::WebPage::*)(WebKit::WebMouseEvent const&)) 16 0x10bdd2483 WebKit::WebPage::didReceiveWebPageMessage(CoreIPC::Connection*, CoreIPC::MessageID, CoreIPC::ArgumentDecoder*) 17 0x10bcd221d WebKit::WebPage::didReceiveMessage(CoreIPC::Connection*, CoreIPC::MessageID, CoreIPC::ArgumentDecoder*) 18 0x10bd4b0a1 WebKit::WebProcess::didReceiveMessage(CoreIPC::Connection*, CoreIPC::MessageID, CoreIPC::ArgumentDecoder*) 19 0x10bc07eac CoreIPC::Connection::dispatchMessage(CoreIPC::Connection::Message<CoreIPC::ArgumentDecoder>&) 20 0x10bc0a6c3 CoreIPC::Connection::dispatchMessages() 21 0x10bc114db MemberFunctionWorkItem0<CoreIPC::Connection>::execute() 22 0x10bc70bcf RunLoop::performWork() 23 0x10bc71b00 RunLoop::performWork(void*) 24 0x7fff89ed0b51 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ 25 0x7fff89ed03bd __CFRunLoopDoSources0 26 0x7fff89ef71a9 __CFRunLoopRun 27 0x7fff89ef6ae6 CFRunLoopRunSpecific 28 0x7fff866273d3 RunCurrentEventLoopInMode 29 0x7fff8662e63d ReceiveNextEventCommon 30 0x7fff8662e4ca BlockUntilNextEventMatchingListInMode 31 0x7fff885db3f1 _DPSNextEvent Expected result: No assert failure.