1738181 - WebExtension Imagus does not show images immediately after hovering on a link

Status: RESOLVED FIXED

(Core :: Graphics: WebRender, defect)

Description

[Fanolian]

Attachment: Image not shown in Imagus pop-up.png

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:95.0) Gecko/20100101 Firefox/95.0
Build ID: 20211027214117

Imagus is an extension to "enlarge images and display images/videos from links with a simple mouse-over". It stops showing images if I don't move my cursor after hovering on a image link.
This is originally reported by gwarser on Reddit.

Steps to reproduce

1. Install Imagus in a new profile.
2. Reload this bug report page. (So Imagus takes effects on this tab.)
3. Hover on this, or any, image link and immediately stop any mouse movements:
   https://i.redd.it/8mo5s0rt12w71.jpg

Actual result

A white pop-up frame is shown but the actual image is not shown. The pop-up frame is an Imagus feature that holds the actual image.
The actual image will be shown, 99% of the time, if I move the cursor slightly. Sometimes if the cursor is already in the pop-up frame, I have to move the cursor a long way, preferably away from the frame, in order to show the image.

The bug, however, does not exhibit on some links with images in smaller dimensions like https://i.imgur.com/UuAxgpA.png.

Expected result

The image should be shown after hovering on the link. Maybe the pop-up frame will flash for a split second but it should not stay.

Notes

Another image pop-up extension/script Mouseover Popup Image Viewer does not exhibit the same issue.

Regression

Last good Nightly: 2021-10-26
First bad Nightly: 2021-10-27
pushlog: https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=7708adfc84d30a2796e1c4c75afcc6147cf2454a&tochange=28be46661ce5b2e858b92549da73d3f8bacd1b20

Bisecting autoland builds:
https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=46e947d2b251e7cb31130b2148e06dd01d08a3df&tochange=c4f073f7e3a347402602313204b98c308b354df3

This is regressed by bug 1711061.

Comment 1

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

Set release status flags based on info from the regressing bug 1711061

Comment 2

[Andrew Osmond [:aosmond] (he/him)]

I am able to reproduce. Investigating now, thanks!

Comment 3

[Jeff Muizelaar [:jrmuizel]]

Attachment: Reduced test case

I can reproduce this with the attached test case.

Comment 4

[Pascal Chevrel:pascalc]

Fixed by backout of bug 1711061