GdkWin32: Fix mouse events in presence of transparent windows on the desktop
Forward-port of !2767 (merged) to GTK4
Fixes: #370 (closed), #417 (closed), gimp#1082 (closed)
Edited by Luca Bacci
Forward-port of !2767 (merged) to GTK4
Fixes: #370 (closed), #417 (closed), gimp#1082 (closed)