Known issus: Popup with “StaysOpen=false” steals PreviewMouseDown event

When we set the Popup with `StaysOpen=false` that will steals the PreviewMouseDown and LeftMouseButtonDown etc event. And this is a known issus. Do we plan to break this behavior? I think it is difficult to understand.

Behavior:

We click the button to open the popup, and then we click a checkbox. We can find the popup close and the checkbox be checked but the PreviewMouseDown event in checkbox will not fire.


Link: https://stackoverflow.com/questions/29889620/popup-with-staysopen-false-steals-leftmousebuttondown-event

The demo: https://github.com/lindexi/lindexi_gd/tree/46e813ad18655df1653e1fb9de6c238f91171443/NayfarwehelaFebeejochar