title: Get the Headersize of a TabControl
body: <p>Is there an elegant way to get the size of this area (or the amount of tabrows)?
  <a href="https://i.stack.imgur.com/d0j2K.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/d0j2K.png" alt="enter image description here"></a></p>
  
  <p>I know I could just add the <code>ActualWidth</code> of each <code>TabItem</code> together and divide it by the <code>TabControl.Width</code>. But I wanted to know, if there was a better way to do it.</p>