You know that bar with the volume percentage that appears on the middle of the screen when you hit the VolumeUP or VolumeDOWN button of the keyboard?

So, when I'm watching a flash video in fullscreen and hit one of the Volume buttons, the bar appears, but the video exits the fullscreen mode.

Is it normal?

I get this also. I note that Dragon Player doesn't do this, so it must be specific to Flash.

Isn't it because of the way KMix operates?

The "layer" that KMix operates the Volume bar is strange for me. It should be "transparent", and work when you are running any program.

I can't do it now, but can someone test how KMix operates when you are playing a game in fullscreen mode. I think, in this case, KMix can not operate, because the game "layer" is in front of it, or something like that.

AFAIK, KMix just displays a single QProgressBar, with the Qt::WindowStaysOnTopHint (and probably Qt::FramelessWindowHint and other hints too).

Flash probably assumes that once it isn't the toplevel widget anymore, it shouldn't be fullscreen, or something like that.

I always thought it was something more specific, maybe the composite keycode of the media keys send a ESC code to fullscreen flash app first or something.. same thing happened with me under every (k/x)ubuntu release the last few years so, i think it's a linux flash / xkb thing and not per se kde related?

This is a well-known bug in flash that has been around a very long time. As far as I know flash developers are aware of it, but I have not heard any indication that a fix is forthcoming.