AS3 Email link issues

I am having an issue with my email link in CS3 using AS 3
the code below works however it opens up a new browser window every time
the contact me button is pressed.
is there any way to get it so it does not do that?

----------------code below------------

contactrt_btn.addEventListener(MouseEvent.MOUSE_DOWN, mouseDownHandler2);
function mouseDownHandler2(event:MouseEvent):void {
navigateToURL(new URLRequest("mailto:[email protected]"));