I'm on OS X 10.9 and with this OS upgrade, the ability to run fullscreen apps on a second display while working on another was implemented.
What I want:
Play YouTube and other online sources (divxstage.eu to name one) videos on my second (1080p) screen while working on my internal MacBook Pro display.
Case (1): Youtube videos can be run in fullscreen mode, so if I click on the button it expands to the whole secondary display. When switching back to my MBP, after a while OR (when in a playlist) upon starting the next video it resizes to only a portion (I believe about the same size of the MBP display!) of the screen in the upper left corner, however cutting off the video and displaying a 3/4 black screen. (Example: if there was a circle in the video, you'd now see like a segment of this circle)
Case (2): I found that with e.g. divxstage.eu, videos do not even expand to the full screen, but leave it blank in 3/4 right away. (Same size as with YouTube videos)
Has anyone experienced this, too? Can anybody help, a possible solution, workaround, or even just the source of the problem?