Hi, I am sorry that you are having this issue with the dishonline full screen. I have reported the issue and I am waiting to hear back. I will let you know when I get a response.
I am having the same issue. New Hopper / Joey installed today and I went ahead and got the sling also. I click on full screen and it will goto that and after a couple minutes, it goes back to the internet window size.
Problem solved by powering modem , router, hub and hopper down and bringing them back up one at a time.
Still can't see any of my recordings through dish online anybody else?