add: if(!(speed[0] || speed[1])) return; 
context:   startScrolling: function(speed) {    this.scrollSpeed = [speed[0]*this.options.scrollSpeed,speed[1]*this.options.scrollSpeed];    this.lastScrolled = new Date();    this.scrollInterval = setInterval(this.scroll.bind(this), 10);  },
meta: 4973	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/4973/30c2487bcd7bbfafc8ec58078b5e75726303cb1d/dragdrop.js/clean/src/dragdrop.js