Fix image artifact in X11 without alpha after zoom (#9774)
Fix image artifact in X11 without alpha after zoom (#9774)

Fixes https://github.com/root-project/root/issues/9763
olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root