Cant disable size sensitivity with tablet, please help


Hi, i bought a tablet to learn zbursh but i have problem with tablet settings, the tablet is called huion wh1409. The program recognizes pressure of a pen, i can see it with increasing z intensity, but i cant disable size sensitivity. I noticed that tablet options in zbrush doesnt effect the drawing, however if turn off the tablet in options i can still draw with it but without any pressure sensitivity at all. I tested this on different versions of zbrush and on my mac but still no result. Maybe someone had this problem or maybe its possible to turn off size sensitivity in other way?
Example with mouth and pen