Additional information that might matter... I have a second monitor connected via HDMI output. Monitor is 1600x1200 and is rotated 90 degrees. It had problems on 18.04 with Wayland (https://bugs.launchpad.net/ubuntu/+source/gnome-shell/+bug/1808226) and I have attached the output of xrandr when run from Xorg.
This does matter. I rebooted with the second monitor not connected and the problem with the menu does not occur.
Additional information that might matter... I have a second monitor connected via HDMI output. Monitor is 1600x1200 and is rotated 90 degrees. It had problems on 18.04 with Wayland (https:/ /bugs.launchpad .net/ubuntu/ +source/ gnome-shell/ +bug/1808226) and I have attached the output of xrandr when run from Xorg.
This does matter. I rebooted with the second monitor not connected and the problem with the menu does not occur.