Right-click menu missing when watching video in fullscreen mode

Yeah, the decision about how to composite hardware accelerated content is usually happening elsewhere, and I think it's inconsistent based on the browser/os/gpu/driver that you're talking about.  The market is pretty fragmented, and there are limits to our ability to abstract it all away.  Chrome generally values security over user experience, and will tend to isolate activities out into individual processes to the extent possible, which may be why they're more constrained in how they handle z-ordering with hardware accelerated streams.

It's also the case that there are a finite number of things that can be hardware accelerated simultaneously, and Flash will fall back to software rendering if it's not available.  When we're rendering in software, we're should honor any specified z-ordering that might be ignored when hardware is in play (e.g. the context menu is displaying on top of the video), but we're using a lot more CPU.

If you're really curious, there's usually some interesting stuff in the "problems detected" section of chrome://gpu, where they list out all of the various workarounds for your specific graphics hardware.

You're really poking at the edges of hardware acceleration support, and more than likely, you're talking about behavior that's going to vary depending on the OS, browser and GPU chipset.  This is one of those places where you still see a lot of fragmentation in the market reflected in the behavior of the software.  The more stable and uniform this stuff is, the easier it is for software companies to provide a consistent, uniform experience across devices.

I provided a link to an example video, but the link has been removed. That's probably ok due to some rules; I'm not complaining, just explaining if you're wondering.