If a song (or video) is actively playing on Windows Media Player and I open a page where there is an HTML5 video in frame (for example, while scrolling FB news feed) it will automatically pause until I either close the page or scroll it out of my viewing frame. How can I tweak this behavior (disable it) while NOT disabling or generally changing the auto play settings for the video (I like to have them play along, especially while the firefox video is muted)?

P.S.: It is really difficult to google the question but I think I am the first asking it.