I am using the new Firefox Developer Edition as a stand-alone on Ubuntu, so I can still use the "old" version, too. Everything seems to be working fine, as in I am logged in and setup sync. But a few features I got very much used to are no longer working. When I click on "About Firefox Developer Edition", it shows these details: --------------------------- Firefox Developer Edition 36.0a2 (2014-12-09) Firefox Developer Edition is up to date You are currently on the aurora update channel. --------------------------- In my "old" Firefox, I can: 1. Click with the mouse wheel on the navigation arrows to open the previous or next page in a new tab. 2. "right mouse click" on the navigation arrows to see the list of previously visited pages of the current tab, and the ones I visited after the page I am on, if I clicked "back" once or more times. I can then click the mouse wheel or "Ctrl + Left Mouse Button" to open any of the pages in the list in a new tab. None of this works in the Developer Edition.