When I maximize some Flash (version 15.0.0.xxx) videos to fullscreen, only the top left quarter of the screen is showing video, the rest is completely black.
I've tried this on OSX 10.9 and 10.10, 2014 Macbook Pro, 3 browsers (Safari, Chrome, and Firefox) with no plugins, no additional screen, and hardware acceleration set to enabled and disabled.
Here's a workaround I've found: right click on the 1/4-screen video and look for the Stretching is <type>
item in the options list. Click on that and the video will fill the screen. Keep repeating to get back to the 'Stretching is none' setting.
What can I do to debug this?