title: Incorrect pixel coordinates
body: <p>I am using the following code to get pixel coordinates of the mouse position.</p>
  
  <pre><code>private void canvas_MouseMove(object sender, MouseEventArgs e)
  {
       startPoint = e.GetPosition(this);
  }
  </code></pre>
  
  <p>However, if the user uses the scroll bar to move down a bit then this code does not work. I get the wrong coordinates and the object does not get drawn under the mouse position. Any ideas what going on here?</p>