title: Why is text in TextBox highlighted (selected) when form is displayed?
body: <p>I have a form containing a <code>TextBox</code> in C# which I set to a string as follows:</p>
  
  <pre><code>textBox.Text = str;
  </code></pre>
  
  <p>When the form is displayed, why does the text in the texbox appear highlighted/selected?</p>