plugins/scroller.js
function(e) {
			var thumbOffset = this.thumb.region().height/2;
			this.setPositionIfValid(e._e.pageY - (this.node.region().top + this.scrollbarOffset) - thumbOffset);
		}
function(e) {
			var thumbOffset = this.thumb.region().height/2;
			this.setPositionIfValid(e._e.pageY - (this.node.region().top + this.scrollbarOffset) - thumbOffset);
		}
function ( e ) { var thumbOffset = this . thumb . region ( ) . height / 2 ; this . setPositionIfValid ( e . _e . pageY - ( this . node . region ( ) . top + this . scrollbarOffset ) - thumbOffset ) ; }
Update the position of the thumb from an event
Update the position of the thumb from an event