ComboBox: different behaviour on windows/linux

[newfla]

I'm experiencing a different behavior of the ComboBox between Windows and Linux.
When it is positioned as the last item (vertically) of a window, the selection popup on Windows is truncated while on Gnome (47 wayland session) it is shown outside the window.
Is this expected behavior?
It might be nice to be able to decide if the popup should be shown above or below the box.

• Windows
  
• Linux
• 

Reproducible example

[Enyium]

I believe there was a PR recently that repositioned the ComboBox pop-up, so everything becomes visible (maybe try the master branch?). But, in the future, such pop-ups should be (frameless) topmost top-level windows, just like in other apps, so they can be drawn outside the window that contains their associated unopened widget.