rem: this.isVertical() ? pointer[1]-offsets[1] : pointer[0]-offsets[0] 
add: (this.isVertical() ? pointer[1]-offsets[1] : pointer[0]-offsets[0])-(this.handleLength/2) 
context:   startDrag: function(event) {    if(Event.isLeftClick(event)) {      if(!this.disabled){        this.active = true;                var handle = Event.element(event);        var pointer  = [Event.pointerX(event), Event.pointerY(event)];        if(handle==this.track) {          var offsets  = Position.cumulativeOffset(this.track);           this.event = event;                   this.setValue(this.translateToValue(             this.isVertical() ? pointer[1]-offsets[1] : pointer[0]-offsets[0]          ));        } else {          // find the handle (prevents issues with Safari)          while((this.handles.indexOf(handle) == -1) && handle.parentNode)             handle = handle.parentNode;                  this.activeHandle    = handle;          this.activeHandleIdx = this.handles.indexOf(this.activeHandle);          this.updateStyles();                  var offsets  = Position.cumulativeOffset(this.activeHandle);          this.offsetX = (pointer[0] - offsets[0]);          this.offsetY = (pointer[1] - offsets[1]);        }      }      Event.stop(event);    }  },
meta: 4973	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/4973/5fa81acc3e4e722f3224e6b94fd578c055cba661/slider.js/buggy/src/slider.js