unable to get full screen with uTube videos
I bought a used Mac-mini 2,1 mid 2007, 1.83GB and 2GB ram. OS 10.6.8 Using Safari I can watch videos, but when I click on full screen, I get a message suggesting the browser doesn't support. I'm using a VGA monitor. On my iMac desktop when that was running snow leopard, I do not recall any trouble with full screen. So I'm puzzled, is there a add-on I need?
iMac, OS X El Capitan (10.11.3), 8GB on 27" 2GB on 17"