title: How to break an infinite loop using previewMouseUp?
body: <p>Currently, I start looping upon <code>PreviewMouseDown</code> and I was thinking to break the loop using <code>PreviewMouseUp</code> but apparently failed. Below is the way I did it.</p>
  
  <pre><code>public bool stopFlag = true;
  public int abc = 0;
  private void TestingDown(){
      while(stopFlag)
      {
         abc++;
      }
  }
  
  private void TestingUp()
  {
      stopFlag = false;
      Message.show(abc);
  }
  </code></pre>
  
  <p>Actually my idea is to create sort of button holding effect, something like smartphone, hold a button for 3 seconds and do something. But there isnt any <code>onHold</code> event for button?</p>