Yes I saw this bug with Firefox in 18.04 yesterday, so it's still an open problem.
Maybe it is just Xwayland, but worth noting I have seen similar issues in gnome-mpv when trying to run it as a pure Wayland app: https://community.ubuntu.com/t/hardware-accelerated-video-playback/304/4 -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to gnome-shell in Ubuntu. https://bugs.launchpad.net/bugs/1706476 Title: Mysterious shadow around window when check marking an option box inside of window Status in gnome-shell package in Ubuntu: Confirmed Status in mutter package in Ubuntu: New Bug description: this mysterious shadow occurs when I click inside an empty option box in a window to download a file from my cloud service. it's the option box for "do this automatically for files like this for now on." the shadow is very brief and completely surrounds the window and is the same shape as the window, square. I've never seen this type of behavior on any version of Ubuntu so I thought it was a bug of some kind worth mentioning and it occurs every time I click the box to select/deselect it. ProblemType: Bug DistroRelease: Ubuntu 17.10 Package: gnome-shell 3.24.3-0ubuntu1 ProcVersionSignature: Ubuntu 4.11.0-11.16-generic 4.11.10 Uname: Linux 4.11.0-11-generic x86_64 ApportVersion: 2.20.6-0ubuntu4 Architecture: amd64 CurrentDesktop: GNOME Date: Tue Jul 25 18:25:25 2017 DisplayManager: gdm3 GsettingsChanges: b'org.gnome.shell' b'enabled-extensions' b"['dash-to-d...@micxgx.gmail.com', 'refresh-w...@kgshank.net']" b'org.gnome.shell' b'app-picker-view' b'uint32 1' b'org.gnome.shell' b'favorite-apps' b"['org.gnome.Nautilus.desktop', 'firefox.desktop', 'thunderbird.desktop', 'hexchat.desktop', 'gimp.desktop', 'libreoffice-writer.desktop', 'libreoffice-calc.desktop', 'org.gnome.Terminal.desktop', 'org.gnome.Calculator.desktop', 'org.gnome.Software.desktop', 'gnome-control-center.desktop']" b'org.gnome.desktop.interface' b'gtk-im-module' b"'gtk-im-context-simple'" InstallationDate: Installed on 2017-07-25 (0 days ago) InstallationMedia: Ubuntu 17.10 "Artful Aardvark" - Alpha amd64 (20170725) ProcEnviron: TERM=xterm-256color PATH=(custom, no user) XDG_RUNTIME_DIR=<set> LANG=en_US.UTF-8 SHELL=/bin/bash SourcePackage: gnome-shell UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-shell/+bug/1706476/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp