If the "Press Escape to exit full screen mode" message stays on your computer screen indefinitely, there are a few steps that will help to resolve this error:
1. Head to your Adobe Flash Player Settings Manager. This will bring you to the Global Storage Settings panel.
2. If it's not already there, drag the slider to 100 KB.
3. Check the box labeled "Allow third-party Flash content to store data on your computer."
4. Then navigate to your Website Storage Settings panel and click Delete all sites.
5. Try playing a video in Full Screen mode
* If the above steps do not work, try going through them again and instead adjust the slider to 1 MB for Step 2.