I've only noticed this recently, in the last few days. It maybe due to bug 683290.
When you have Zimbra in a background tab for a while, then switch back, many of the images don't show up. The regular folder icon on the left side shows up, but the icons for "sent" "drafts" "junk", and the various icons on the main toolbar across the middle (new, get mail, delete, etc.) don't show up. Interacting with the page a little brings it back to some extent.
Okay, it does show the icon for "sent", "new" and "translate".
Similar problem on Pandora. There's a cloud image in the background that isn't displayed if you flip to another tab for a while, then switch back.
On Pandora, image is reshown when you scroll up and down.
When I load dslreports.com, the images for the main toolbar (home, reviews, tools, forums, etc.) are not immediately displayed. Switching to another tab and back does show them, as does reloading. Doing a hard reload (command-shift-R on OSX) and they disappear again until I switch to another tab.
Also, I tried an 8/14 nightly at Kyle's request, and it did not show the symptoms in Comment 0-2.
https://odesk.com/ doesn't show the background image (a bunch of people) on initial load.
I and brson are seeing this on Linux as well. Started over the last few days.
odesk.com is working for me now, so maybe it was just site slowness.
*** Bug 784068 has been marked as a duplicate of this bug. ***
Alice's regression range in bug 784068 points at khuey's patch.
(In reply to Andrew McCreight [:mccr8] from comment #7)
> odesk.com is working for me now, so maybe it was just site slowness.
Still present for me in zimbra.
Bisecting the range from dupe bug 784068 comment 5, the first bad revision is
user: Kyle Huey <email@example.com>
date: Mon Aug 13 15:04:19 2012 -0700
summary: Bug 697230: Part 1 - Centralize style image observers. r=bz
(Same as causes the permaorange in bug 651866.)
Bisecting methodology: Open zimbra, browse to another tab, wait 1.5 minutes, go back. In the bad case most of the images vanished and only reappear on clicking on the page.
Created attachment 653585 [details] [diff] [review]
There is an optimization to avoid invalidating frames before the first paint (since there is no existing data that is now invalid). The way we listen for paints is flawed, and sometimes we don't realize that a paint has occurred and fail to invalidate when we should. roc thinks this optimization is probably unnecessary, since invalidating these frames should be cheap. This patch removes that optimization.
*** Bug 783355 has been marked as a duplicate of this bug. ***
*** Bug 783126 has been marked as a duplicate of this bug. ***