My keyboard has a volume knob. I've set the properties of a knob on my GUI to increment and decrement with the volume up and volume down, respectively. I figured this would map to the knob on the keyboard. I've mapped the knob on the GUI it to other keys available in the properties box (e.g. <page up> and <page down>). The rest work fine. Any clue on why the volume knob wouldn't work or how I can make it work?