Brush draws when Im not applying pressure

I have a windows tablet PC that has pressure sensitivity - Vaio Canvas Z. I have the wintab and wacom drivers installed for pressure sensitivity to work. When I’m drawing in toon boom, and only in toon boom, not photoshop or animate, the brush begins to draw before I’ve even touched the pen to the tablet surface. There should be no pressure sensitivity, at all, because I’m not applying pressure.

Any ideas?