Host key (ctrl) sometimes gets stuck down in Windows guest

[myxiplx]

Not all the time, but regularly enough to be a nuisance, the host key gets stuck down within the guest after it's been used to free up the mouse. Does VirtualBox always send the "key-up" message to the guest after the host key has been pressed?

I'm running VirtualBox full screen on my second monitor, and often hit ctrl so that I can leave the virtual machine running, but free the mouse so I can continue working on my primary screen.

After doing this, about a quarter of the time, I go back to the guest to find the control key stuck down. It means typing is impossible, and unlocking a machine with your password is a nuisance until you spot what is going on. Tapping the left control key on the keyboard does seem to free it up again.

I also run the VMware Infrastructure Client within this virtual machine, and that requires the use of Ctrl+Alt to free the mouse from its client windows. A couple of times now that has wound up locking the mouse and keyboard within VirtualBox when I come back to it, and it appears to coincide with times the control key has gotten stuck down. I'm reporting this here instead of as a separate bug as I think it's just another symptom of the same problem.

For now I've changed my host key to the Scroll Lock button, that appears to be a useful workaround for now.