--- D:/Downloads/qt-everywhere-opensource-src-5.5.0/qt-everywhere-opensource-src-5.5.0/qtquickcontrols/src/controls/qquickmenu.cpp	Mon Oct 19 16:53:48 2015
+++ D:/Develop/Libraries/Qt/5.5.0_vs2013/qtquickcontrols/src/controls/qquickmenu.cpp	Mon Oct 19 14:15:38 2015
@@ -459,6 +459,9 @@ void QQuickMenu::__popup(const QRectF &targetRect,
 
         m_popupWindow->setPosition(targetRect.x() + m_xOffset + renderOffset.x(),
                                    targetRect.y() + targetRect.height() + m_yOffset + renderOffset.y());
+
+        QMetaObject::invokeMethod(m_popupWindow, "updateSize", Qt::QueuedConnection);
+
         emit aboutToShow();
         m_popupWindow->show();
     }