function adjustBehaviour()
{
   var oldPlayFunc = this.Pl;
   this.Pl = function(){
      oldPlayFunc.call(this);
      this.GE('spinner').style.visibility = "visible";
   }

   var oldStopFunc = this.St;
   this.St = function(){
      oldStopFunc.call(this);
      this.GE('spinner').style.visibility = "hidden";
   }
}