User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.9; rv:28.0) Gecko/20100101 Firefox/28.0 (Beta/Release) Build ID: 20140218122424 Steps to reproduce: 1. Visit a page on our site such as: https://lumi.do/topic/Mozilla/ (no login required to view) and scroll down. 2. As you scroll down we add items to the DOM and attempt to lazily JS load the correct image for brick 3. After a few scrolls the images will fail to paint correctly and you'll be left with a grey background where an image should be (as seen in the screenshot attached). Inspecting the page will show that the image is 'there' and has been loaded correctly. If you continue to scroll or manually invoke our paging JS to load/unload items that are 'out of sight' then the images on the bricks become visible. Expected results: Images are painted.

Additional comments as I should've used the advanced form - this is reproducible in Firefox 27, 28 and today's Nightly. Also the box model in the inspector seems to be claiming that the affected elements are 0x0 in size despite widths and heights despite all being correctly set.

Um... if it's there but the wrong size, that's a layout issue, no?

Do you see this in 26 as well? Or did it start in 27?

Just downloaded and reproduced in 26 on Mac. I can keep going back if that's helpful as annoyingly I don't have an exact reproduce time from our side aside from 'a while'. Obviously this works correctly in 'like Gecko' renderers.

Er, apologies, I didn't mean to move component there.

Mainly I wanted to know if it is a relatively recent regression in Firefox, which it sounds like it is. Thank you.

Er, sounds like it _isn't_, no? I can reproduce in Firefox 26 on Mac pretty easily.

I can reproduce since Firefox6. (I cannot test on Firefox5 and earlier version because it fails to load initial page) http://hg.mozilla.org/releases/mozilla-release/rev/5b6c2f8ff6da Mozilla/5.0 (Windows NT 6.1; WOW64; rv:6.0.2) Gecko/20100101 Firefox/6.0.2 ID:20110902133214

Yes, correct - from what I can see it's not a recent regression.

(In reply to Boris Zbarsky [:bz] (reviews will be slow; ask someone else) from comment #7) > Er, sounds like it _isn't_, no? > > I can reproduce in Firefox 26 on Mac pretty easily. Sorry, my mistake.

This seems similar to bug 926155, and might be related.

With these, the site doesn't work at all: 2009-10-27-03-mozilla-central-firefox-3.7a1pre.en-US.linux-x86_64 2010-10-01-03-mozilla-central-firefox-4.0b7pre.en-US.linux-x86_64 2011-01-01-03-mozilla-central-firefox-4.0b9pre.en-US.linux-x86_64 With these, I am not sure when/whether to consider the bug reproduced: 2012-06-24-03-05-37-mozilla-central-firefox-16.0a1.en-US.linux-x86_64 2014-05-22-03-02-04-mozilla-central-firefox-32.0a1.en-US.linux-x86_64

I now no longer work at Lumi - I'll obviously do what I can to help solve the bug but I don't have as any control over the contents of the site anymore.

Seems like the layout of the site has changed. The site still uses infinite scrolling, but I'm not seeing any image loading issues with it. I'm going to close this out as worksforme, but feel free to reopen it if there are sites that still reproduce.