The position of the save bar should probably be pinned to the bottom of the viewport. Instead, the save bar can disappear when scrolling up, and can float into the content area of the page when scrolling down. In both cases, the save bar is wily and will snap back to the bottom after random events such as clicking anywhere on the screen.
I believe all browsers are affected, but anyway I'm using Firefox on Debian.
Steps to reproduce:
- Open the beta features preference tab.
- Scroll up and down.
Screenshots: