PopupContent occludes the MessageBox

Hello,

WPF Popups are set to be "topmost" in Windows and WPF doesn't provide an option to change that.  PopupButton uses the standard WPF Popup so it's unfortunately out of our control.

Your options would be:

1) Redesign your UI so that you aren't using a popup that stays open when a MessageBox is displayed.

2) Redesign your UI so you should the message in some other way than a MessageBox.

3) Look at possible workaround described online like in this StackOverflow thread or this MSDN article.  Many of the workarounds described in those require Win32 API calls that would fall outside the scope of our support since this issue is in Microsoft's core WPF code and can be reproduced without our controls.