title: How to make an expandable button toolbar
body: <p>I have a navigation panel in the left hand side of my WPF application. I want to make a button (like in photoshop or a similar program) when you push it, it expands across the bounds and "on top" of the other controls (the center column) - and allowing the user to push a button. Just like in the ribbon bar.</p>
  
  <p>Does it make sense?</p>