I'm trying to get a button that filters out clicks based on transparency mask of a background image.

E.g. when I set FormBorderStyle to (none) and TransparencyKey to MyFormImage.GetPixel(0,0), then make a button with no border and a background image that uses the same transparency mask, I get the behavior that I want on the button, but it also punches a square hole in the form - not what I want.

Moreover, by using .maketransparent on the button image, I get the look, but not the behavior - same as clicking in a rectangular region.

Is there a simple way to make this work?

Any manual alternatives are looking rather involved if I happen to have multiple or overlapping buttons.

If not, can I turn off the border that appears around the button region during a click action?