Instead of 'vol bar get stuck on screen' I started to think 'vol bar staying activated', which raised the question, 'why?' I imagined the answer would be, either the keyboard volume knob is continuing to send a up or down signal to the PC and PC is responding by raising or lowering the volume all the way up or down, and since the keyboard is continuing to send the signal, the on screen bar is remaining activated. Well, last week I noticed for the first time that instead of going all the way up, it is going all the way down to 0% and volume bar staying on the screen. I even did a system restored but the problem came back. I tried many things, tweaked many settings, even uninstalled sound card driver, keyboard driver everything and then re-installed. So every time I rotate the volume knob on the keyboard, the on screen volume bar would operate properly (up or down) but as soon as I let the knob go, the bar would go all the way back up to 100% and stayed there.

I use Microsoft SideWinder X6 Multimedia Keyboard. On my Windows 10 System I was getting the volume bar just like the picture posted by DavidHK129 automatically keep going all the way up to 100% and then stuck on the screen.