I take it back. It works randomly, sometimes. Possibly related to Gnome Tweak Tool > Windows > Titlebar Actions, but that does not seem to do what it's meant to reliably either.
** Changed in: gnome-shell (Ubuntu) Status: Fix Released => Confirmed -- You received this bug notification because you are a member of Ubuntu Desktop Bugs, which is subscribed to gnome-shell in Ubuntu. https://bugs.launchpad.net/bugs/1698083 Title: Vertically maximize on middle button click does not work in Wayland sessions To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-shell/+bug/1698083/+subscriptions -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs