title: Unity 2D - OnMouseDown() not working
body: <p>When clicking a UI image I made, the 'void OnMouseDown()' function do not work!
  Things I have tried:</p>
  
  <ol>
  <li>List item</li>
  <li>put it in a canvas</li>
  <li>reimporting assets</li>
  <li>setting z to -1</li>
  <li>setting box collider in the good size</li>
  <li>setting box collider 3D instead of 2d
  None of this worked for me, please help me!</li>
  </ol>
  
  <p>My script:</p>
  
  <pre><code>public class btnPlay : MonoBehaviour, IPointerDownHandler {
  
      Vector3 pos;
  
      // Update is called once per frame
      void Update () {
          pos = new Vector3 (Screen.width / 4.6f, Screen.height / 1.58f, -1f);
          transform.position = pos;
      }
  
      void OnPointerDown(PointerEventData p) {
          Debug.Log ("X");
          SceneManager.LoadScene ("Level");
      }
  }
  </code></pre>