Button event with transparency

1

Hi people !
This is my first thread. I searched google a lot but didn’t found a reasonable sollution for what I need, so I’m thinking you could help me out.

Here’s the code:

// add the images
var region1_on:Loader = new Loader();
region1_on.contentLoaderInfo.addEventListener(Event.COMPLETE, region1OnLoad);
region1_on.load(new URLRequest("assets/region1on.png"));
            
var region1_off:Loader = new Loader();
region1_off.contentLoaderInfo.addEventListener(Event.COMPLETE, region1OffLoad);
region1_off.load(new URLRequest("assets/region1off.png"));
        
        
// build the button
var region1_button:SimpleButton = new SimpleButton(region1_off, region1_on, region1_on, region1_on);
addChild(region1_button);

Here’s a demo

The problem is that even though the background of the image is transparent, the event is attacched to the entire image, instead to what’s visible.

Is there a property tht needs to be set to the SimpleButton object in order to make the event react only to non-transparent bitmap data ?