title: WPF RichTextBox - Replace Selected Text with Custom Control
body: <p>Before I start hacking in a really crude solution, I thought I'd see if someone could give me a little nudge in the right direction.</p>
  
  <p>What I really want to do is let a user select some text in a RichTextBox, click a button, and convert that text into a custom rendered control.  Convert it to a Button containing the text they had selected, for instance.</p>