How to create a custom shaped button
The custom shaped button is based on a mask that will determine the shape of the button: creating a mask is very simple because all you need is a picture file that can be easily created using an image editor. Here follows a little tutorial that will demonstrate how to proceed.
The first thing to do is to create a picture file, like the one you can see below, containing a bitmap that will be used as a mask for determining the button final shape.
Once You have created the bitmap file you have to:
Set the Shape property to SHAPE_CUSTOM
Set the PictureCustom property to the picture file containing the mask bitmap you just created.