I can resize the brush through the mousewheel or by positioning the pointer and hitting up and down or [ and ]. Once I get between size 7 to 10 (depending on feathering size) and 27 to 33 (depending on feathering size) the graphic goes crazy and it doesn't display a circle anymore. It's almost like it's zoomed in WAY too much and displays only part of the circle. Once I get to size 34-100 it fixes itself again. I can change up and down just fine with the arrow keys or brackets. If I go above 34 with the mouse wheel it creates another problem. Sizes 19-33 start to look normal but once I hit size 18 I get 2 adjustment brushes showing. Once I go down to size 9 I get 4 adjustment brushes showing up. This also makes the mouse pointer show up 4 times throughout the whole program for the rest of the time it's open.