User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:20.0) Gecko/20100101 Firefox/20.0 Iceweasel/20.0 Build ID: 20130402195902 Steps to reproduce: If i look into the source code of a website (via context menu "View Page Source" or via STRG + U) the page source code always gets opened in a new window. Actual results: The page source code gets opened in a new window and not in a new tab. Expected results: Sience Firefox is based mostly on tabs it should open the page source code in a new tab like Chrome, Opera, ... . Or if you don't want to change the behavor, make it optional.