Hello! I recently updated my clip studio paint app and it's been working beautifully, however, I recently tried to make a custom brush with the register material feature. I followed the instructions and used the gray expression color and set the shape as the brush tip, but the color is acting odd. There are three different color options for a brush at a time, the primary color, the secondary color, and the transparent version. For some reason, my brush ONLY works for the secondary color and does not have a transparent counterpart. Am I doing something wrong? Please help!