Fractional scaling: Firefox extension windows extremely slow
Affected version
- Ubuntu 20.04.2 LTS
- Gnome 3.36.8
- X.Org 1.20.9
- Firefox 90.0
- Extension: Bitwarden 1.51.1
Hardware:
- Asus UX31A laptop
- Intel® Core™ i5-3317U CPU @ 1.70GHz
- RAM: 4 GB
Bug summary
When fractional scaling is activated in Gnome settings, opening Firefox extensions' child windows becomes incredibly slow. I tested the password manager Bitwarden and Ublock Origin. Even when typing a password in those child windows, it takes 2 seconds for each character to appear.
Steps to reproduce
- Install Firefox browser from Ubuntu repository
- Install Bitwarden extension in Firefox (it works normally and fast at this point)
- Activate fractional scaling in Gnome settings
What happened
As soon as fractional scaling is activated, Bitwarden and other extensions become unusably laggy and make the browser unusable too. Other applications (outside Firefox) as well as Firefox naked (without extensions) seem unaffected by the lagging issue.
What did you expect to happen
Extension should work as speedily as without fractional scaling.
Relevant logs, screenshots, screencasts etc.
about:performance in Firefox shows no particular load for Firefox when this happens. I'm not a developer myself. Please let me know if there are any other logs or technical info I can supply to help fix this. Thank you!