QSystemTrayIcon menus displayed below toolbar

My app uses a system-tray context menu as its main menu. On Qt 5.0.0, when I right-click the icon, part of the menu appears below the space where the icon is (whether that be the system tray itself, or the pop-up for surplus icons that is accessed by clicking the arrow next to the tray). If it is the tray itself, the tray partly obstructs the menu, making the lowest action in the menu inaccessible. The attached screenshot shows what is happening.

More info: Still, when giving the Menu in the examples\widgets\desktop\systray a 0-parent, the menu is on top for me.