1818869 - Firefox UI glitches and flashes during Reflow Timer Test

Status: RESOLVED FIXED

(Core :: Graphics: WebRender, defect)

Description

[Gregory Pappas [:gregp]]

Attachment: glitching.webm

Steps to reproduce:

1. Navigate to https://reflow-timer-test.appspot.com/shared/index.html
2. Click 'Run and send results to Browserscope'

Actual results:
Firefox UI glitches and flashes

Expected results:
Firefox UI does not glitch or flash

I got this regression range but I'm not confident that its correct
https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=b422dd886e036907f35269f381f43785873c5296&tochange=69be3221f49a2acb92b734baf725e19bdf9a4fd9

Comment 1

[Timothy Nikkel (:tnikkel)]

This looks very similar to bug 1805347. Same regression range I think. Likely same cause.

Comment 2

[Alice0775 White]

On Windows10, window control buttons(minimize, maximize, close) blink if Titlebar is disabled(default).
Sometimes, tab title blink.
Regression window:
https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=042779b7d50b41810724223ca2cf84fc473be387&tochange=b508157c9213b7237a7d600b8b98359fbd4067d5

Comment 3

[BugBot [:suhaib / :marco/ :calixte]]

The severity field is not set for this bug.
:gw, could you have a look please?

For more information, please visit auto_nag documentation.

Comment 4

[Gregory Pappas [:gregp]]

No longer able to reproduce.

Using mozregression, I got bug 1863620 as the fix. That seemed a bit strange, so I bisected again and still got bug 1863620. Then, I did another two runs with overlay scrollbars disabled (widget.gtk.overlay-scrollbars.enabled:false) and got a different bug, bug 1870803.

Guessing that the core issue is still present, but these two changes (bug 1863620, bug 1870803) have papered over it?

Comment 5

[Glenn Watson [:gw]]

Yea, I think this is probably the same underlying cause I've identified for 1840988 and 1805347, and it's going to be quite random as to whether a page is able to visibly see glitches depending on a heap of factors. Working on a proper fix for it though.

Comment 6

[Mayank Bansal]

What you can still repro is that the drop-down on address bar will become blank.

STR:

1. Set gfx.webrender.debug.force-picture-invalidation= true
2. Follow the STR from comment #0
3. Click on the address-bar (such that the drop down is visible)
   AR: the dropdown is blank.

Comment 7

[Mayank Bansal]

Attachment: Bug-19Feb2024.mp4

Comment 8

[Gregory Pappas [:gregp]]

No longer able to reproduce the issue on Linux in a local build that includes bug 1881978.