Tested with: Device: Samsung Galaxy Nexus (Android 4.2.1), Nexus 4 (Android 4.4) Steps to reproduce: 1. Open https://bug705506.bugzilla.mozilla.org/attachment.cgi?id=577122 Expected results: - Fixed elements should stay fixed to the viewport. Actual results: - The fixed footer from the bottom of screen is displayed in the middle of the page. Please see the attached screenshot.

Regression window-wanted: 1. mozilla-central: good build: 07-01-2015 bad build: 08-01-2015 pushlog: http://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=33781a3a5201&tochange=70de2960aa87 2. inbound: good build: 1420648378 bad build: 1420648560 pushlog: http://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=6399ee520bcc&tochange=a4c67bb878ff

I can repro this. Will investigate.

This is broken on B2G as well. Based on my investigation so far, I believe the problem is that the calculation of the |aPreviousTransformForRoot| argument for |AsyncCompositionManager::AlignFixedAndStickyLayers| [1] needs to be updated to reflect the changes in bug 1076241. [1] http://mxr.mozilla.org/mozilla-central/source/gfx/layers/composite/AsyncCompositionManager.cpp?rev=15a1d3459835#265

It's nice when a fix to a bug consists of removing a piece of code that was arbitrary-seeming to begin with :)

Comment on attachment 8547784 [details] [diff] [review] bug1120400.patch Review of attachment 8547784 [details] [diff] [review]: ----------------------------------------------------------------- I don't understand this code, but having less of it is good :)

Try push that includes this patch: https://treeherder.mozilla.org/ui/#/jobs?repo=try&revision=8f40f1b579f6

(In reply to Botond Ballo [:botond] from comment #6) > Try push that includes this patch: > https://treeherder.mozilla.org/ui/#/jobs?repo=try&revision=8f40f1b579f6 Had to cancel that one due to a mistake an a different patch it included. Here's a new Try push, and it's green: https://treeherder.mozilla.org/ui/#/jobs?repo=try&revision=f5237502df73

Comment on attachment 8547784 [details] [diff] [review] bug1120400.patch Approval Request Comment [Feature/regressing bug #]: Bug 1076241. [User impact if declined]: Fixed-position layers are mispositioned. [Describe test coverage new/current, TBPL]: Tested locally, and landed on m-c. [Risks and why]: Low; it's a small, straightforward, and isolated change. [String/UUID change made/needed]: None.

(In reply to Botond Ballo [:botond] from comment #11) > Comment on attachment 8547784 [details] [diff] [review] > bug1120400.patch > > Approval Request Comment > [Feature/regressing bug #]: Bug 1076241. > [User impact if declined]: Fixed-position layers are mispositioned. > [Describe test coverage new/current, TBPL]: Tested locally, and landed on > m-c. > [Risks and why]: Low; it's a small, straightforward, and isolated change. > [String/UUID change made/needed]: None. Note that the regression and the fix only affect APZ platforms (by default, just B2G) and Fennec.

The fixed footer from the bottom of the screen is displayed correctly at the bottom of the page, so: Verified as fixed on: Device: Samsung Galaxy Nexus (Android 4.1.2) and Nexus 4 (Android 4.4) Build: Firefox for Android 38.0a1 (2015-01-15)

Comment on attachment 8547784 [details] [diff] [review] bug1120400.patch Aurora+