title: How to make two controls apear as focused?
body: <p>I'm trying to write a custom control, that have a TextBox and a ListBox inside it's template.
  But I've found that when I entering a text in the TextBox (so TextBox has focus), ListBox appears as not focused. This makes my control looks like two different controls.</p>
  
  <p>I've read at MSDN that in the WPF there is something called FocusScope but I didn't succeed with it.</p>
  
  <p>So my question is how can I make both ListBox and TextBox controls appear as focused when one of them has keyboard focus within?</p>