Description of problem: Firefox on Wayland fails to scale to a higher DPI screen when a lower DPI screen is attached. Other "native" gnome apps correctly scale when switching screens, e.g. Terminal, Settings, Files. Version-Release number of selected component (if applicable): firefox 65.0-4.fc29 gnome-shell 3.30.2-1.fc29 linux 4.20.7-200.fc29 waylandpp 0.2.3-2.fc29 Steps to Reproduce: 1. Using a high-dpi laptop display at 200% scale, plug in a lower DPI monitor at 100% scale 2. Start Firefox Actual results: When Firefox windows are on the low DPI external monitory, they'll be a reasonable size. When they're on the laptop screen, they're 2x too small. The cursor, icons, etc. are all too small. The cursor returns to normal size when it leaves the window. Expected results: The cursor and Firefox should be visually the same (or very similar) size on the high DPI screen as they are on the low DPI screen.
Here's another user with the same issue: https://www.reddit.com/r/firefox/comments/8sq9ri/firefox_on_hidpi_screens_linux/
Can you please test with this build https://koji.fedoraproject.org/koji/taskinfo?taskID=33603998 ? It's Firefox 66 candidate. Also I can't reproduce on Fedora 30 / FF66 - maybe it's Fedora 29 specific issue?
(In reply to Martin Stransky from comment #2) > Can you please test with this build > https://koji.fedoraproject.org/koji/taskinfo?taskID=33603998 ? It's Firefox > 66 candidate. Also I can't reproduce on Fedora 30 / FF66 - maybe it's Fedora > 29 specific issue? Thanks for the recommendation! I can confirm that the firefox 66 candidate is still bad when run as the "Firefox" .desktop entry, but using the "Firefox on Wayland" launcher item installed by firefox-wayland-66.0-5.test.fc29.x86_64.rpm fixes the issue! It now scales as well as the Terminal, Settings, and Files apps. Extension context menus and pop-ups are broken and show up at half-size but that deserves its own ticket. Thanks again for your help!
Created new ticket for the invisible window issue: https://bugzilla.redhat.com/show_bug.cgi?id=1690363