Steps to reproduce:

1. Visit about:preferences#search
2. Click the default search engine dropdown

What happens:

The menu appears away from the dropdown

Expected result:

The menu should appear attached to the dropdown

So it's Wayland specific bug?

I'm actually unsure if it is Wayland specific; this is the regression range:

15:34.26 INFO: Narrowed inbound regression window from [b558ba47, b067a5b1] (3 builds) to [b558ba47, 93d4fceb] (2 builds) (~1 steps left)
15:34.26 INFO: No more inbound revisions, bisection finished.
15:34.26 INFO: Last good revision: b558ba472e668f18999200d08d07a0f2c2475cdb
15:34.26 INFO: First bad revision: 93d4fcebc9d7a0d2ade280e634f2864ce8004335
15:34.26 INFO: Pushlog:
https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=b558ba472e668f18999200d08d07a0f2c2475cdb&tochange=93d4fcebc9d7a0d2ade280e634f2864ce8004335

I'll try removing export MOZ_ENABLE_WAYLAND=1 from my profile and report back.

Yes, it seems to be Wayland specific.

Pushed by ccoroiu@mozilla.com:
https://hg.mozilla.org/integration/autoland/rev/aa776e6ed29a
[Wayland] Don't position windows with zero height/width, r=jhorak

https://hg.mozilla.org/mozilla-central/rev/aa776e6ed29a

Comment on attachment 9069345 [details]
Bug 1555866 - [Wayland] Don't position windows with zero height/width, r=jhorak

Beta/Release Uplift Approval Request

• User impact if declined: Wrong popup position on Wayland (extend Bug 1550051 to some corner case when popup is not initialized yet).
• 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: Low
• Why is the change risky/not risky? (and alternatives if risky): Minor fix, Wayland/Linux only.
• String changes made/needed:

Comment on attachment 9069345 [details]
Bug 1555866 - [Wayland] Don't position windows with zero height/width, r=jhorak

wayland fix for 68.0b8

https://hg.mozilla.org/releases/mozilla-beta/rev/aa42e8f17f87