User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:87.0) Gecko/20100101 Firefox/87.0

Steps to reproduce:

1. Opened firefox snapped to half-width on a 1440p display
2. Opened https://gerrit.opnfv.org/gerrit/c/laas/+/72126
3. Expanded the diff for actions.py in the site (this causes a horizontal scrollbar to appear)
4. Used touchpad to zoom out from current state (no zoom-in gesture was performed prior, site scaling settings were unchanged from default)

Actual results:

The site allowed a zoom out, and then showed visual artifacting (see attached photo)

The view is occluded by some white bounds, and scrolling is strange in this state.

Trying to zoom back in causes more strange behavior.

Expected results:

At least no artifacting should occur, potentially I should not be allowed to pinch-zoom out on this page when the horizontal size changes to be larger than viewport.

(In reply to Sawyer Bergeron from comment #0)

3. Used touchpad to zoom out from current state (no zoom-in gesture was performed prior, site scaling settings were unchanged from default)

Hmm, is this maybe linux only? I tried on my mac and nothing happened when I tried to zoom out.

Also couldn't reproduce on Windows.

(In reply to Timothy Nikkel (:tnikkel) from comment #1)

(In reply to Sawyer Bergeron from comment #0)

3. Used touchpad to zoom out from current state (no zoom-in gesture was performed prior, site scaling settings were unchanged from default)

Hmm, is this maybe linux only? I tried on my mac and nothing happened when I tried to zoom out.

What do you see when you expand the file on mac? If the window isn't narrow enough to cause the horizontal overflow after the expand then it doesn't trigger for me. It also doesn't trigger if the window is narrow enough to cause overflow in the first place, but that's hard to do with the given layout.

I'll see if I can go through and see if an about:config pref triggers it later this week. I'm currently running on webrender with the touchpad-zoom gtk pref enabled. I'm attaching the full list from dumping about:support.

You have apz.allow_zooming_out=true set :)

This is not a default configuration precisely because issues around zooming out like this have not been ironed out on desktop.

I can confirm this problem with apz.allow_zooming_out is still reproducible on Firefox 103.0.1 on Windows 11. And Firefox 91.11.0esr on Mobian cell phone.

This problem is not limited to desktop nor linux. It can be reproduced also on Windows 11 desktop and Mobian linux ARM64 cell phone.