[Interest] Fixing screen-reader when using composition on VLC 4.x

[Benjamin Arnaud]

Dear Qt enthusiasts,

I'm part of the development team on the VLC project, specifically on the 
upcoming Qt / QML desktop interface.

In order to preserve compatibility (and performances) we're using 
composition to render our video frames with a QML UI on top. 
Unfortunately it prevents screen-reader events to be dispatched on X11 
(Orca). Here's our entry point for UI composition on X11: 
https://code.videolan.org/videolan/vlc/-/blob/master/modules/gui/qt/maininterface/compositor_x11.cpp#L151

Like mentioned in this thread, the D-Bus events are sent just fine on 
X11 *but* the active window seems to be wrong, so the OS ignores these 
entirely: 
https://code.videolan.org/videolan/vlc/-/issues/27171#note_337868

That's a bit advanced, but if someone has a clue on how to fix this we 
would greatly appreciate it.

Regards,
---
Benjamin Arnaud