title: Scrolling to an element of a virtualising ItemsControl
body: <p>I have a <code>ItemsControl</code> which displays its items in a <code>ScrollViewer</code>, and does virtualisation. I am trying to scroll that <code>ScrollViewer</code> to an (offscreen, hence virtualised) item it contains. However, since the item is virtualised, it doesn't really exist on the screen and has no position (IIUC).</p>
  
  <p>I have tried <code>BringIntoView</code> on the child element, but it doesn't scroll into view. I have also tried manually doing it with <code>TransformToAncestor</code>, <code>TransformBounds</code> and <code>ScrollToVerticalOffset</code>, but <code>TransformToAncestor</code> never returns (I guess also because of the virtualisation, because it has no position, but I have no proof of that) and code after it never executes.</p>
  
  <p>Is it possible to scroll to an item with a virtualising <code>ItemsControl</code>? If so, how?</p>