After loading the Home page of Youtube with cobalt, it can not exit cobalt by pressing the return key, if fact, when play the video, it can return back to the home page by pressing the return key, so it seemed the youtube page does not process the return key when it's on the home page, it's convenient if Youtube can support it as some other platforms(eg opera browser) with youtube has such feature.
Keep the useragent format as youtube needed(Browser_Name/Browser_Version, Device_Name/Firmware_Version (Brand, Model,Connection_Type)), then it can response the return key, and it will show the exit dialogue.