OK, I did it and now it seems working without a hitch. Maybe that bug reapper, maybe not. If it does I will record it to prove it's true but I hope it will never do.

Thanks for respond.

Sure. I used Windows 7 and latest beta as of 2 days ago (believe it's 4.5.10.10). Task Panel was on the right side, vertically. One of icons was Nvidia's tray icon. Even after I started scrolling to chage volume I got appeared baloon messages from Nvidia tray icon if arrow was on it and from others if arrow was on others. Sometimes just freezes of vlume control even when nothing appeared.

I immediately went back to stable version and all was cool again.