Emulated flexbox doesn't support this, but allows you to specify widths
in percentages instead, so do that.

This shouldn't have any observable behavior change, but this is the
first page that uses modern flexbox layout instead of XUL layout.

In practice, this means that various interesting bugs that arise from
poor interaction between xul and block / flex / grid should disappear /
no longer be an issue for front-end developers.

Depends on D157073

This shouldn't have any observable behavior change, but this is the
first page that uses modern flexbox layout instead of XUL layout.

In practice, this means that various interesting bugs that arise from
poor interaction between xul and block / flex / grid should disappear /
no longer be an issue for front-end developers.

Note that this depends on bug 1790303.

Comment on attachment 9294176 [details]
Bug 1790307 - Use modern flexbox in about:addons. r=#extension-reviewers

Revision D157075 was moved to bug 1790308. Setting attachment 9294176 [details] to obsolete.

https://hg.mozilla.org/mozilla-central/rev/646ae1f6d62c
https://hg.mozilla.org/mozilla-central/rev/fd57a3ea2b88

Emilio, I know you've put up patches for a bunch of the regressions but given soft freeze has now started, should we consider backing out the second patch here and relanding it after soft freeze to give ourselves some time to address any fallout, discovered or otherwise?

Yeah. Most fixes are one-liners, not super-concerning, but that's fair.

We'd need to back out both patches tho, otherwise the applications menu would be broken (because width: 50% doesn't work on XUL)... Would it be reasonable to back both out from beta as soon as the merge happens? Alternatively I guess we can back them out today, and I can reland after the soft freeze, if you want.

(In reply to Emilio Cobos Álvarez (:emilio) from comment #8)

Would it be reasonable to back both out from beta as soon as the merge happens? Alternatively I guess we can back them out today, and I can reland after the soft freeze, if you want.

I think backing out today and relanding on Monday/Tuesday is the easiest in that you don't need to request approval for anything (sheriffs will back you out on request), but I don't have a super strong preference either way.

Backed out as per Emilio's request.

Backout link

I asked sheriffs to back out, will re-land on monday after the freeze is over.

Backout merged to central: https://hg.mozilla.org/mozilla-central/rev/f848304d50f3

https://hg.mozilla.org/mozilla-central/rev/f848304d50f3

https://hg.mozilla.org/mozilla-central/rev/fa16221c24fe
https://hg.mozilla.org/mozilla-central/rev/0bd09bf30151