title: XAML TextBox inside Popup gets hidden by on screen keyboard
body: <p>In my metro application, I have a page full of TextBoxes that are laid out vertically inside a  StackPanel. Normally, when the user clicks one of the bottom textboxes, the page automatically scrolls upwards so that the focused textbox is not obscured by the on screen keyboard. </p>
  
  <p>But this automatic scrolling doesn't seem to happen if the page is displayed inside a Popup. What should I do to make my Popups have the same scrolling behavior as normal pages?</p>