Comment 54 for bug 555408

That's what I suspected, but wanted to be clear. I did try today downloading VirtualBox, adding myself to the vboxusers group, reboot, and run Shotwell (outside and inside the virtual machine) with the Kensington wireless mouse and trackball, with and without a USB hub, and failed to reproduce this.

Not saying this isn't an interesting path to follow, but it wasn't an immediate win on my end. Perhaps there's another piece to the configuration puzzle I'm missing here.