I have a typical problem and see the solution like that one everywhere: Can't disable hardware acceleration in Adobe Flash Player 188.8.131.52 on Ubuntu
Yet, there's a bit of a problem:
There is NO box there, so nothing to click at!
The point is that Chrome can't display videos. Only sound. But If I turn to full-screen mode it starts working. But only until I try to switch back to windowed mode.
When I press "settings" no box appears. When I press settings in a full-screen mode, a box appears, but there are only "privacy" "storage" "microphone" and "camera" tabs there. Nothing about visualization of the Hardware Acceleration!
I tried re-installing adobe flash player (11.7), updating it, installing the previous (11.6)version (it all started today) clearing cache and cookies. Nothing works. I guess it's yet another "in the face" update that installed itself. I'm turning off auto-updates. Faith in Adobe -2 faith in Chrome -1.