title: WPF textbox usercontrol containing custom items, not simple text
body: <p>I'd like to have a custom usercontrol based on textbox where I could type in text (for example names) and the names would be then converted to custom items (that would have an X button to remove them, etc). This is what I would like:</p>
  
  <p><img src="https://i.stack.imgur.com/OFYkH.png" alt="alt text"></p>
  
  <p>How can I achieve this? Can I replace a piece of text with a custom item?
  Thanks for any ideas.</p>