
We want to clip it away if 1) The window is fully opaque or 2) If it's translucent but has a frame (as explained in the comment above). The code didn't quite match and we were only applying it on case #2. Case #1 is far more common, and saves us from pushing some drawing that we know will be covered in the end. https://gitlab.gnome.org/GNOME/mutter/merge_requests/698