Crash when clicking on flash player while flash plugin no installed

When you don't have flash plugin install in your Mac and you go to a website embedding a flash player (e.g http://www.alsacreations.fr/dewtube.html), when you left or right click inside the area where the flash player is suppose to be it crashes with the following call stack.

It happens on every flash player I tried with the Browser demo on Qt 5.3.1 (GCC 4.8) on Mac OS 10.7 & 10.9.

Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
0 QtWebKit 0x0000000105591028 WebCore::PluginView::setCallingPlugin(bool) const + 8
1 QtWebKit 0x0000000105321914 WebCore::PluginView::dispatchNPCocoaEvent(_NPCocoaEvent&) + 52
2 QtWebKit 0x00000001053218d2 WebCore::PluginView::setFocus(bool) + 82
3 QtWebKit 0x0000000105feb6e8 WebCore::Document::setFocusedElement(WTF::PassRefPtr<WebCore::Element>, WebCore::FocusDirection) + 1752
4 QtWebKit 0x00000001054bf4d3 WebCore::FocusController::setFocusedElement(WebCore::Element*, WTF::PassRefPtr<WebCore::Frame>, WebCore::FocusDirection) + 1027
5 QtWebKit 0x00000001054b0ea3 WebCore::EventHandler::dispatchMouseEvent(WTF::AtomicString const&, WebCore::Node*, bool, int, WebCore::PlatformMouseEvent const&, bool) + 579
6 QtWebKit 0x00000001054b0623 WebCore::EventHandler::handleMousePressEvent(WebCore::PlatformMouseEvent const&) + 1523
7 QtWebKit 0x00000001051d8e5d QWebPageAdapter::mousePressEvent(QMouseEvent*) + 445
8 QtWebKitWidgets 0x000000010514cd8a QWebPage::event(QEvent*) + 522
9 QtWebKitWidgets 0x0000000105151755 QWebView::mousePressEvent(QMouseEvent*) + 37
10 QtWidgets 0x00000001083b94da QWidget::event(QEvent*) + 1466
11 QtWebKitWidgets 0x00000001051513a3 QWebView::event(QEvent*) + 83