The font size increase from bug 1701920 had a knock on effect on padding in some panels (i.e. the AppMenu) which we should bring back to spec with this bug.

Looking at the padding of the AppMenu surrounding the panel, it's set at 8px, which is per-spec. Did you mean to have this be in em units to be proportional to font size? Or were you referring to different padding, and not the edges of the panel?

What other panels and what other padding does this bug refer to?

To be clear, the Figma specification supplies a font size that's in pixel values. We made a conscious decision in bug 1701920 to use em units to inflate the font size of panels and dialogs to match the font size in the URL bar, per UX request. Since this font size is different from platform to platform (and from OS configuration to configuration - like DPI settings), being "on spec" for font size across the board is not really an achievable goal in any meaningful sense.

Since the width of the panels is also dependent on that dynamic / per-platform / per-configuration font size, having a static width in all configurations is also not achievable.

So it's really not clear to me what's being asked for here.

ni'ing emanuela - have we misinterpreted the UX guidance on how to set the font size in these panels and dialogs?

Reverting bug 1701920 is the decision that Product and UX have come to. Unfortunately, enough time has passed since bug 1701920 landed that this is not a straight backout. I will prepare a new patch to revert the change in this bug.

https://hg.mozilla.org/mozilla-central/rev/1160a9696e13

Comment on attachment 9218399 [details]
WIP: Bug 1706415 - Revert Proton font-size changes for panels and modals from bug 1701920. r?Gijs!

Beta/Release Uplift Approval Request

• User impact if declined: Required for MR1 / Proton
• Is this code covered by automated tests?: No
• Has the fix been verified in Nightly?: No
• Needs manual test from QE?: No
• If yes, steps to reproduce:
• List of other uplifts needed: None
• Risk to taking this patch: Medium
• Why is the change risky/not risky? (and alternatives if risky): This is mostly a backout, but because the patch that we're backing out is from a few weeks back, it wasn't a straight back-out. Because of that, and because this covers so many different panels, I'm going to say this has medium risk.
• String changes made/needed: None.

Comment on attachment 9218399 [details]
WIP: Bug 1706415 - Revert Proton font-size changes for panels and modals from bug 1701920. r?Gijs!

Approved for 89 beta 6, thanks.

https://hg.mozilla.org/releases/mozilla-beta/rev/674cb1c12e2b