Firefox 66 and Mesa 19.0 ended up in the release pocket. So we are now more or less feature complete.
You can test the state of the Firefox Wayland support by following those steps:
Start the Ubuntu-Wayland session instead of the “ubuntu” one.
Open the terminal (gnome-terminal or whatever)
- After testing just close the terminal. The env variable in step 3 was just set temporarily, so the next time you start up Firefox it will use X(wayland) again.
Initially I saw just invisible windows. It turned out, that I had Webrender still enabled in about:config accidentally after an unsuccessful Webrender tryout.
EDIT 2 Just as an information: It seems that GDK_BACKEND isn’t supposed to be set globally. It is designed to be set per application. So don’t try to set it up globally, it will probably just not work or even prevent to start the desktop session. If you want Firefox to start up automatically, you will probably have to edit the firefox.desktop file (instead of
Exec=firefox %u use
Exec=env GDK_BACKEND=wayland /usr/bin/firefox %u. That will pass the per application env just to Firefox.