Cross 2.6 mix control

I am having a problem adjusting the mix "knob" on the top middle of the screen. When I move the cursor up to the knob it will say Cue Mix, but when I click on it to lower the mix the pointer disappears. It makes the preview useless because even if the cue buttons are not pushed the tracks that are playing come in to loud. I am using the Vfx controller. I do love Cross DJ and have used it with NO problems. It is very reliable. Hope you can help me out with this. Is there a key combination that will lower the mix?
Thanks again,
Mike "Maddog" Duffy
Thanks again,
Mike "Maddog" Duffy