After bug 1792881, if you find something without result,s the findbar and panel content etc move.

Looking a bit deeper into it I understand the problem now, and bug 1792881 isn't the right fix.

This fixes bug 1792881 in a way that actually preserves behavior from
before bug 1790307.

The main difference between modern flexbox and XUL is that size of
contents outside of the scroller (main-content) affect the size of the
scroller, preventing it from flexing if they're bigger than the
available size.

Instead, preserve the previous behavior (flex the scroller) by
preventing the minimum size from being taken into account, by using
contain. While at it, merge two selectors that were spread out.

Set release status flags based on info from the regressing bug 1792881

Setting to P1 since emilio is on the case.

The bug is marked as tracked for firefox107 (nightly). However, the bug still has low severity.

:yshash, could you please increase the severity for this tracked bug? If you disagree with the tracking decision, please talk with the release managers.

For more information, please visit auto_nag documentation.

https://hg.mozilla.org/mozilla-central/rev/9840551d4951

clearing needinfo as this has been closed/fixed

I managed to reproduce this issue on a 2022-10-04 Nightly build on macOS 12. Verified as fixed on Firefox 107.0b4(build ID: 20221023190001), Nightly 108.0a1(build ID: 20221023100414) on macOS 12, Windows 10, Ubuntu 22.