Found in

• Firefox 105.0b4

Affected versions

• FIrefox 105.0b4
• Nightly 106.0a1

Tested platforms

• Ubuntu 22.04
• Windows 10
• macOS 12

Affected platforms

• Ubuntu 22.04

Unaffected platforms

• Windows 10
• macOS 12

Preconditions

• browser.search.region = US.
• Firefox is opened in a Wayland session.

Steps to reproduce

1. Launch Firefox in a wayland session.
2. Go to about:preferences#privacy.
3. Scroll down to the "Forms and Autofill" section.
4. Click on "Saved Addresses" button.
5. Click on "Add".
6. Click on the Drop-Down menu from the "State" section.

Expected result

• The drop-down is displayed normally, user can select a state.

Actual result

• The drop-dows is unusable and it flickers very badly.

Regression range

• Will look for one ASAP.

Notes

• This does not reproduce on X11.

I believe bug 1786525 would fix this.

Can you test latest nightly?
Thanks.

Hy,
I can still reproduce on 2022-09-02 Nightly.

I managed to get a manual regression range for this one:

• last good: 2022-08-15

• first bad: 2022-08-16

• pushlog: https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=1c3c5be93f5897f3265ec5eeef08c09cb09fb774&tochange=52232c1ea77d7fc9154ff8f7e82a3b0796983288

Please run with MOZ_LOG="Widget:5, WidgetPopup:5" and attach the log here.
Thanks.

Hello,
Here are the logs.

Do you have layout.css.devPixelsPerPx set?

layout.css.devPixelsPerPx is set by default to -1.0 on Nightly. I tested it with the following values:

• -1.0 reproduces;
• -0.5 reproduces;
• 0 reproduces;
• 0.5 does not reproduce;
• 1 reproduces;
• 1.5 does not reproduce;
• 2 does not reproduce;

I'd also like to mention that on the cases where the bug does reproduce, browser window has to be maximized.

Probably dupe of bug 1789581

I have the same issue. I run Fedora 36 with Gnome 42.4 and Firefox 105.0.1. From my understanding (findings) this might be caused by the increasing of the text scaing in the OS. I for example use 100 scaling on a 13 inch laptop and the "bigger text" accessibility feature. Without this I don't have this issue. layout.css.devPixelsPerPx is set to -1.0

Can you please try latest nightly (https://fedoraproject.org/wiki/How_to_debug_Firefox_problems#Testing_Mozilla_binaries) and if you still see it, can you provide a reproduction steps? Which page do you use to reproduce it?
Thanks.

Ah, I see the 'Steps to reproduce'. Will try so.

I tried various scales but I can't reproduce it with latest nightly.

I can still reproduce on 2022-10-04 Nightly with browser.search.region set toUS and layout.css.devPixelsPerPx set to -1.0. The browser window needs to be maximised in order to reproduce.

Okay, then please attach the popup logs from nightly again - run with MOZ_LOG="Widget:5, WidgetPopup:5" on terminal.
Also please attach your about:support page.
Thanks.

Thanks, I'll test that on Ubuntu 22.04 then.

Tested the same configuration with various scales but I'm unable to reproduce.

I think I managed to reproduce it while debugging something else. Looks like we don't set nsView::mDimBounds. The error sequence is:

1. move-to-rect callback is called
2. we set new nsWindow::mBounds (smaller) but keep original large nsView::mDimBounds
3. nsView::DoResetWidgetBounds() is called where newBounds = CalcWidgetBounds(type); is called:
   https://searchfox.org/mozilla-central/rev/1564027eba41993868973e4a7b93bea942a16b78/view/nsView.cpp#313
   newBounds is based on old mDimBounds:
   https://searchfox.org/mozilla-central/rev/1564027eba41993868973e4a7b93bea942a16b78/view/nsView.cpp#212
   so curBounds.Size() != newBounds.Size(); is triggered:
   https://searchfox.org/mozilla-central/rev/1564027eba41993868973e4a7b93bea942a16b78/view/nsView.cpp#351

and we're resizing the widget again. So it looks like we need to also update nsView::mDimBounds from move-to-rect callback.

So that's usually happening as a result of layout. It happens on trunk because of https://bugzilla.mozilla.org/show_bug.cgi?id=1795294

Not sure why but I can't reproduce that on latest trunk.

Ardelean, can you please test on latest trunk? I suspect some of the latest fixes (Bug 1793609, Bug 1792839) may affect this one too.
Thanks.

Re-tested and Bug 1795294 fixes the flickering for me.

Unfortunately, I can still reproduce this on Nightly 108.0a1(2022-10-18) on my Ubuntu 22. However, I asked 2 of my colleagues to try and test this bug to see if they can reproduce it, and they were unable to. The only anomaly one of them noticed was that right after opening the " Saved Addresses" window and "State" dropdown, the list flickered for a split second and then worked properly. The other colleague could not reproduce at all. I'm assuming that perhaps there's something amiss with my Ubuntu configurations and as such I cannot 100% say if the bug has been fixed or not.

Do you have any other interesting configuration... Fractional monitor scaling? Font settings? Large fonts? Some other DPI related thing?

Nothing out of the ordinary.

• Landscape orientation;
• Standard 1920x1080(16:9) resolution;
• Fractional Scaling is disabled;
• Scale value at 100%;
• Default Font Settings;
• Large Text is disabled;

Marking as RESOLVED WORKSFORME since I can't reproduce this bug anymore on the most recent Nightly build.