Embedding Youtube in Tableau with Full Screen

In my recent design of the Khan Academy Viz, I came across an issue: The embedded Youtube video player in Tableau is not showing full screen button (only after published to the server). A video player without full screen is unthinkable and I need to find a solution.

I was using a method proposed by Tableau's product marketing manager Ben Jones. The format proposed is as follows:
http://youtube.com/embed/yx1S_o741kI

After digging around, I found this note on Google. The solution is using "v" instead of "embed" in the embedded URL:
http://youtube.com/v/yx1S_o741kI

V will instruct the use of AC3 player while Embed will use HTML5 player.

If you publish embeded Youtube videos using AC3 player, the full screen button will show. Why embedded HTML5 player does not show full screen button is beyond my comprehension.

In passing, I found there is a bug in Tableau Desktop when dealing with AC3 player. To reproduce the bug, just download the Khan Academy viz, and click on any of the video titles and you will see something like the screenshot below. This only happens in desktop. The workaround is to close the web object and reenter the url. Do not click on any link though. When published to the server, the player works fine. I submitted a case report #01169202 to Tableau Software.