I've just started noticing this behaviour as well, particularly with Firefox, after switching from Wayland to Xorg on a fresh install of 17.10, gnome-shell 3.26.2-0ubuntu0.1, 1920x1080.
I've just started noticing this behaviour as well, particularly with Firefox, after switching from Wayland to Xorg on a fresh install of 17.10, gnome-shell 3.26.2-0ubuntu0.1, 1920x1080.