When I click a YouTube link in Firefox Mobile 23, Firefox brings up the video's webpage. If I click to play the video, that brings up the YouTube app (plugin?) and plays the video. However, I cannot then exit the YouTube app, and the app replaces Firefox in my window list. That is, there is no longer an entry for Firefox in the window list. If I hit the back key to exit YouTube, it brings me out of that video's page and to a general YouTube front page. This YouTube front page is listed in the window list as Firefox, but it is clearly the YouTube app (plugin?) interface, and there is no way to exit it. The only way to get Firefox back is to stop the app from the window list and restart Firefox. How do I stop this annoying behavior?