Comment 5 for bug 1750889

I'm seeing something similar on Bionic when using the Communitheme on Wayland session, where the scrollbar also goes past the bottom of the window. It does not show up when using Xorg. I think the problem also appears under the Ambiance theme on Wayland, but I do not have a screenshot immediately available demonstrating this. The severity of the problem seems to change depending on the theme used.

(I originally reported my issue here: https://github.com/Ubuntu/gtk-communitheme/issues/199)