11:39:32random-nickI found out that if I patch mcclim's clx backend to always request composited windows then the issue is much more consistent (works on gnome on xorg in the vm, works without display compositing on xfce4, doesn't disappear when I hover the close button or move/unfocus the window)
11:43:10random-nickredirectwindow is supposed to be called by compositors in order to tell xorg to render the window in a image buffer instead of directly on the screen, but it seems that compositors don't always call that and in some cases might unredirect windows