ShowPopup behavior on Windows: Shadowed Box fails to close on internal focus loss

Targets Windows
1

Hi everyone,

I’ve noticed an inconsistent behavior when using DesktopWindow.ShowPopup on Windows, depending on the window’s Type.

When a window is shown using ShowPopup, it is expected to close automatically when it loses focus. However, if the window’s frame is set to Shadowed Box, it behaves differently depending on where the user clicks:

  1. Clicking another application: The window loses focus and closes as expected.

  2. Clicking another window within the same application: The window does not lose focus and stays open, behaving almost like a Modal window within the app’s scope.

If I change the frame type to Plain Box, the behavior is correct: the window loses focus and closes immediately regardless of whether I click another window in the same app or a different application altogether.

Is this a expected behavior or known limitation of the Shadowed Box frame type on Windows?

Thanks.