What is that at the bottom of the screen where the status bar should be?!?

Can anyone help tell me what that peach colored (which is the browser’s theme color) bar is in which the status bar should be, shown on the bottom of this screenshot and how to remove it?

It cause my view to become narrower in addition to making the browser stretch past the monitor, preventing me from viewing that part as there is no way to scroll to that part.

On an unrelated topic, will IceDragon will ever adopt electrolysis E10S? I find that it to be more stable and less prone to crashes.

Also when I open SpeedTest website (www.speedtest.net) on IceDragon, while the page opens, the Flash part of the page does not load. It claims I do not have Flash installed, which I do, and the latest version at that. It is however fully working on Firefox. This is the only known Flash website that has this problem.