, Duncanma wrote

upgraded to 4.0.50917.0 ... still works

I'm not sure which other sites are using the new full-screen pinning feature, but I'll make a simple test player and perhaps we can see if it fails for you as well

 

So I noticed that the same SL player is used on http://live.visitmix.com and I have no problems there, or any other site (including my own).