STR: 1. Open some random tabs that aren't pinned. 2. Open gmail and pin that tab. 3. Click on a link in a gmail email so that it opens in a new tab. Expected behavior: The new tab should open in between the pinned tab and all the other tabs in the tab strip. Actual behavior: The new tab open at the end of the tab strip. There's some code in browser.js that deals with app tabs [1], but I'm not sure if it's related to this problem. [1] http://mxr.mozilla.org/mozilla-central/source/browser/base/content/browser.js#3463