title: How set the focus of a input-TextField without having a stagereference?
body: <p>I got a text-InputField:</p>
  
  <pre><code>var textfield:TextField = new TextField();
  textfield.text = "";
  textfield.type = TextFieldType.INPUT;
  addChild(textfield);
  </code></pre>
  
  <p>because this textfield don't reside in the main-class, I don't have a stage-reference for doing:</p>
  
  <pre><code>textfield.stage.focus = textfield;
  or 
  stage.focus = textfield
  </code></pre>
  
  <p>How can I force the textfield to display the blinking line at position zero?</p>