Excellent - your screen capture was just what we needed to reproduce the issue.
In my case I was not seeing the 'Do you want to allow this website to run in full screen mode' dialog because I had previously checked on the 'Remember my answer' checkbox. If this is not checked on I see the issue, but once checked the problem disappears. I think in most cases this will provide a good workaround, but I will also enter a bug report for this issue
Thanks
Mike