title: Problems with OnMouseDown() event Unity
body: <p>I am new to Unity and I am doing some tutorials, but one drove me crazy. I have a rotating cube with a box collider on it. All events work except OnMouseDown(). I don't know what is the problem... Here is a snippet of code.</p>
  
  <pre><code>void onMouseDown() {        
      Debug.Log ("On Mouse Down Event!!!!!!!!!");
  }
  
  void OnMouseUp() {
      Debug.Log("On Mouse Up Event");
  }
  
  void OnMouseOver() {
      Debug.Log("On Mouse Over Event");
  }
  
  void OnMouseEnter() {
      Debug.Log("On Mouse Enter Event");
  }
  
  void OnMouseDrag() {
      Debug.Log("On Mouse Drag Event");
  }
  </code></pre>
  
  <p>In the console, the message "On Mouse Down Event!!!!!!!!!" doesn't appear not matter my great number of clicks on the cube.</p>