Unity 4.6 Beta Draggable Gui Class

using UnityEngine;
using UnityEngine.UI;
using UnityEngine.EventSystems;
using System.Collections;

public class Draggable : MonoBehaviour, IPointerDownHandler, IPointerUpHandler {
    public Transform target;
    private bool isMouseDown = false;
    private Vector3 startMousePosition;
    private Vector3 startPosition;
    public bool shouldReturn;

    // Use this for initialization
    void Start () {

    }

    public void OnPointerDown(PointerEventData dt) {
        isMouseDown = true;

        Debug.Log ("Draggable Mouse Down");

        startPosition = target.position;
        startMousePosition = Input.mousePosition;
    }

    public void OnPointerUp(PointerEventData dt) {
        Debug.Log ("Draggable mouse up");

        isMouseDown = false;

        if (shouldReturn) {
            target.position = startPosition;
        }
    }

    // Update is called once per frame
    void Update () {
        if (isMouseDown) {
            Vector3 currentPosition = Input.mousePosition;

            Vector3 diff = currentPosition - startMousePosition;

            Vector3 pos = startPosition + diff;

            target.position = pos;
        }
    }
}