title: How to set cursor position in TextInput in Kivy
body: <p>I'm trying to figure out how to keep the focus on my <code>TextInput</code> widget, after calling the <code>on_validate()</code> method. Such that, after hitting RETURN I can keep typing without having to select the widget with my mouse. </p>
  
  <p>When I read the <code>TextInput</code> doc all the cursor options seem to be assuming that the cursor is already in the widget.</p>