Questions on Color Mask/Radius and Drop Shadows

Just to confirm what I suspect after experimenting, adding a mask to a color field appears to override the radius setting resulting in squared-off corners. The only way to have both rounded corners and a mask is for the mask to have rounded corners, correct?

Is there a guide/tutorial on how to use the drop shadow properties? I know that there is some way of adding drop shadows, but I can't find a clear explanation as to how.