title: Synchronize scroll for two RTBoxes
body: <p>I have two RichTextBoxes on my C# main form. Both RTBoxes are with SrollBars=None. They are used to visualize contents of two different files of different size. How can I use separate VScollbar to navigate through text of those RTBoxes simultaneously?</p>
  <p>Browsing forums got a hint to use:</p>
  <pre><code>SendMessage(rtBox1.Handle, (uint)WM_VSCROLL, (UIntPtr)SB_LINEDOWN, (IntPtr)(0)).
  </code></pre>
  <p>But I'm completely lost in synchronizing of scrolling for the two RTBoxes.</p>
  <p>The idea of scrollbar is to show contents of the files synchronously like when <code>VScrolbar.Value=50</code> both RTBoxes present text at the middle of the files (sorry for my English). Any piece of real code is highly appreciated!</p>