Hey Matt. Here's the story Asa has prepared. Please outline the work items. If you feel the number of work items will carry over an iteration please let me know and we'll divide it. Once you have the work items laid out let me know and I'll move everything over to Iteration #4.

I added one work item (bug 851130) for moving the content into a browser element, which is our plan to make the start page faster by taking advantage of async panning and zooming. I also added a dependency on work bug 851130 (integration with AsyncPanZoomController) since we won't see the full benefit until that work lands. This story is ready to move into iteration 4.

Thanks Matt. I'm moving it now.

Went through the following "Story" for iteration #13 without any issues. Used the following build: http://ftp.mozilla.org/pub/mozilla.org/firefox/nightly/2013-08-31-03-02-24-mozilla-central/ Awesome work! Really like how smooth it is now, having over 20 tabs opened still gives the user a smooth experience. - Went through the attached story in comment #0 without any issues - Opened 25 different tabs and ensured that scrolling through them was smooth - Swiped the Tab Navigation Bar and watched the tabs scroll through without any issues. Swiped it the other direction watching the tabs scroll by themselves without any issues - Swiped the Navigation App Bar back and forth while it was moving without any issues (Example: Swipe to the right and then in the middle of the scrolling swipe back to the left) - Ensured that the Navigation App Bar slides into view and then retracts without any issues & jank - Ensured that the Navigation App Bar scrolling is still smooth after closing several tabs - Went through the above test cases in filled view without any issues Issues: When creating new tabs while having several tabs opened, you'll notice some jank when the new tab slides into the navigation app bar. Created Bug 911526