Hello PATATMOZ, you will have to create the browser.tabs.remote.force-enable :-) # In the [[Awesome Bar - Search your Firefox bookmarks, history and tabs from the address bar|address bar]], type '''about:config''' and press the '''Enter''' key. # The about:config "''This might void your warranty!''" warning page may appear.<br> Click '''I accept the risk!''' to continue to the about:config page. # Now right-click anywhere(except from the search field) and choose New and then Boolean # type (or copy/paste from here) '''browser.tabs.remote.force-enable''' and click OK. # In the open "Enter boolean value" pop up, click True and click OK. You have your preference now. If you want to delete it sometime then right-click on it and select Reset. more info for about:config : http://kb.mozillazine.org/About:config thank you