ui.AreaHandler.MouseCrossed() no longer called after call to MouseEvent()

[MMulthaupt]

On Windows, if MouseEvent() has been called for an Area's AreaHandler (for example by clicking on it), no more calls to the handler's MouseCrossed() function will happen anymore, ever. This does not happen on Kubuntu, where MouseCrossed() still gets called when moving the mouse over the area.