I just want to add that I am having the exact same issue. This only happens while viewing vieos in the Bing search engine.
Here are the steps to recreate the issue:
Open IE or Chrome, it happens in either.
Go to http://bing.com
Search Bing for the content I am looking for
Click the videos heading
Click on a video I would like to watch
Click the full screen button
System:
Brand new installation of Windows 8.1. I noticed the issue on the same day of the installation so the chance of a virus, malware or any other malicious program causing the issue are next to none.
Notes:
I only have the problem while watching videos on Bing.
Here is a video of the issue:
REMOVED
Johnathan