Gtk 3.24.5: border-radius on menus looks broken
Menus with rounded corners look broken on non-composited X11 displays (black where the window should be transparent):
For reference, window manger is i3, but I was able to reproduce this using openbox and xfwm.
Running compton to enable compositing doesn't fix this issue for openbox and i3, but enabling compositing in xfwm4 fixes it.