While playing a Youtube video in fullscreen mode the journal text remains visible as a layer on top of the video (first screenshot).
I experimented a bit and found that the overlay issue arises within Chrome (version 42.0.2311.135 m), IE and maxthon work ok,
and only when the video is started from the Main Stage Panel. (second screenshot)
Another video issue with Chrome is playing another Youtube video from within a journal text section, it works allright but in fullscreen the screen flashes for short and then reverts tot the default view, but showing another section of the journal.
It can be solved though by changing the Story Journal Map layout to floating panel instead of side panel. So there is a workaround, but I still think it is worth mentioning.
Another workaround is to disable fullscreen mode by removing allowfullscreen="1" in the HTML code.
I would like to now if these issues are known in the community or is there another cause/solution?