title: TabControl with Add New Tab Button (+)
body: <p>What is the proper way of adding a '+' button tab at the end of all the tab items in the tab strip of a tab control in WPF?</p>
  
  <ol>
  <li>It should work correctly with multiple tab header rows.</li>
  <li>It should be at the end of all tab items</li>
  <li>Tab cycling should work correctly (<kbd>Alt</kbd> + <kbd>Tab</kbd>), that is, the <code>+</code> tab should be skipped.</li>
  <li>I shouldn't have to modify the source collection I am binding to. That is, the control should be reusable.</li>
  <li>The solution should work with <a href="https://en.wikipedia.org/wiki/Model%E2%80%93view%E2%80%93viewmodel" rel="noreferrer">MVVM</a></li>
  </ol>
  
  <p><img src="https://i.stack.imgur.com/hnIXE.png" alt="Enter image description here"></p>
  
  <p><img src="https://i.stack.imgur.com/ac1SE.png" alt="enter image description here"></p>
  
  <p>To be more precise, the button should appear exactly as an additional last tab and not as a separate button somewhere on the right of all tab strip rows.</p>
  
  <p>I am just looking for the general approach to doing this.</p>
  
  <p>Google throws many examples, but if you dig a little deep none of them satisfy all the above five points.</p>