1041729 - When changing tabs between two full-page-zoom'ed tabs, only upper-left region gets invalidated

Status: RESOLVED DUPLICATE of bug 1041200

(Core :: Layout, defect)

Description

[Daniel Holbert [:dholbert]]

STR:
 0. Have a debug build (I've only reproduced this in debug builds, so far; not in nightly)

 1. Load these two URLs, in adjacent tabs:
  data:text/html,<div%20style="height:100%;width:100%;background:lime">abc
  data:text/html,<div%20style="height:100%;width:100%;background:red">abc

 2. Use "Ctrl +" to zoom in a few times in each tab (doesn't necessarily have to be the same amount)

 3. Switch back and forth between the tabs.

ACTUAL RESULTS: Only an upper-left area of the tab is repainted. (The higher the zoom-level, the smaller the area)

Comment 1

[Daniel Holbert [:dholbert]]

Hmm; I can reproduce this on my desktop machine at work (in two different debug builds), but not on my laptop.

[Removing a few local-hacks-that-I-don't-expect-to-influence-behavior to see if they might be responsible...]

Comment 2

[Daniel Holbert [:dholbert]]

Never mind, I can reproduce this on both my desktop and my laptop, with a TBPL-generated debug build from:
 https://tbpl.mozilla.org/?rev=0dc711216018
 http://ftp.mozilla.org/pub/mozilla.org/firefox/tinderbox-builds/mozilla-central-linux64-debug/1405947507/

...and with the opt build from the same cset:
http://ftp.mozilla.org/pub/mozilla.org/firefox/tinderbox-builds/mozilla-central-linux64/1405947507/

So I'm guessing this is just a very-recent regression.

Comment 3

[Daniel Holbert [:dholbert]]

Attachment: screencast

Here's a screencast of the bug, using the opt m-c build from TBPL mentioned in previous comment.

Comment 4

[Daniel Holbert [:dholbert]]

(Paint flashing confirms that only the upper-left region is getting repainted -- as you might expect, based on the symptoms displayed in the screencast)

Comment 5

[Daniel Holbert [:dholbert]]

(I initially thought this might be due to OMTC, since that was briefly turned on and then off today, in bug 994541.  But I don't think that's responsible, because layers.offmainthreadcomposition.enabled is set to 'false' (by default) in the build I'm testing.)

Comment 6

[Alice0775 White]

Maybe duplication of Bug 1041200

Comment 7

[Daniel Holbert [:dholbert]]

Yup, looks a lot like it, based on the symptoms. Thanks!