It is sometimes preferable to avoid skinning a button, letting the user seemingly interact with a background image or video while actually selecting an invisible button placed on top.

To summarize, you can:

1. Create a Simple button and modify its Appearance properties. Simply change the "Opacity" Property to 0 or set "Outline color" and "Fill Color" to #00000000 (including the A value - i.e. alpha channel / transparency), and turn on the "Flat" property. You must also delete the "Text" label.
   
   
   OR
   
   
2. Create an Image button by adding a Simple button, opening the All Properties panel and changing the Container "Style" property to "Image button". Do not associate any image with either the "Pressed image" or "Released image" parameters in the Image category.