MouseLeave event sometimes not fired in floating windows

[zokradonh]

The MouseLeave event is sometimes not fired if you leave a control that is in a floating window and leave the complete floating window area. If you move the mouse very slow, then it is fired most of the time.

Example Video:

In the first part of the video you can see standard working behavior. In the second part the anchorable is dragged out to be a floating window. The MouseLeave tests fail sometimes and the background stays red despite the mouse being outside of the application.

This also affects the WPF property IsMouseOver.

Example Project: https://github.com/zokradonh/avalonissue