Smaller windows squishing bigger windows

System settings seem to have a smaller max size and it cannot grow beyond that, even then it is taking the entire screen at the right squishing firefox. It becomes better when I move firefox to right, it takes all space it could. It feels as if settings is reporting more width than it can actually take.

https://github.com/user-attachments/assets/13c9fa38-198c-47f6-8289-a20e008c5bef

Reproduce the layout shown in the attached evidence with System Settings and Firefox, then investigate the window-sizing behavior that makes the smaller window consume too much width. Done means the larger window is no longer squished in the same arrangement and the reported sizing matches the space the window can actually occupy.

Written by the indexing model from the issue text.