In one our project page it was requested to show the silver light content in Full screen, with out IE headers, tool bars etc., you can achieve this by simply pressing F11. I guess it is a power option and most of the users would not know this command. One option is document it and train. I guess you all know how that one goes. I knew there was a solution to this problem since I have seen examples of silver light media playing movie clip in full screen mode. I looked around on net and found the following link. But before you go there and try out, it will not work in SL4. I am putting the link for documentation purpose of the initial approach taken in SL2.
The concept is straight forward. If the full screen option is selected, the browser host will blow up to full screen. Something changed from SL2 and SL4. After more research on the web, found the solution in the following link and I thought I share it with you for anyone looking for full screen solution in SL4. The link is not only to identify what changed in SL4 to get full screen mode but also all the changes in SL4. This is a good reference to have, since most of the net searches bring back SL2 or 3 version of solution, refer the following to find if it changed or not. If changed what is the correct way to do it in SL4.