How do I get rid of the blank browser window on an email button

1

when I click on the button it opens the mail program fine but I get a blank browser window everytime.

bouton_mail.addEventListener(MouseEvent.CLICK,mail);
function mail(e:MouseEvent):void {
var sendEmail:URLRequest = new URLRequest("mailto:contact@chiberta-golfwear.com");
navigateToURL(sendEmail);
}

Thank you for your help.

Emmanuel