ZBrushCentral

Masking in combination with texture doesn't work

Helo to you all i’m a newbie, perhabs this is a stupid question but i’m trying to put a texture on a object by masking, only the “Mask By Hue” stays grey(also Mask By Saturation, and Mask by Intensity) i can’t activate it, masking by alpha does work, what do i wrong.

with friendley greetings Silberdenar