title: Get rid of the transparency of a progress bar control
body: <p>While there are several questions about how to make a WinForms <a href="http://msdn.microsoft.com/en-us/library/4z6ak4h9.aspx" rel="nofollow noreferrer"><code>ProgressBar</code> control</a> transparent, I am facing the opposite:</p>
  
  <p><img src="https://i.stack.imgur.com/VJTIo.png" alt="Progress bar under Windows XP"></p>
  
  <p>I.e. I am having a WinForms form (called from an <a href="http://www.add-in-express.com/" rel="nofollow noreferrer">Add-in Express</a> Outlook add-in) that contains a progress bar. </p>
  
  <p>On Windows 7, everything looks fine, but on Windows XP, the progress bar's background seems to shine through (as you can see in the screenshot).</p>
  
  <p>One special thing is that the <a href="http://msdn.microsoft.com/en-us/library/system.windows.forms.form.formborderstyle.aspx" rel="nofollow noreferrer"><code>FormBorderStyle</code> property</a> of the form is set to <code>None</code>.</p>
  
  <p><strong>My question is:</strong></p>
  
  <p>Does anyone know the reason for this (unwanted) transparency and how to get rid of it?</p>
  
  <p><strong>Update/solution:</strong></p>
  
  <p>Thanks to <a href="https://stackoverflow.com/questions/12622440/get-rid-of-the-transparency-of-a-progress-bar-control#comment17018342_12622440">John's answer</a> I figured out that the form's <a href="http://msdn.microsoft.com/en-us/library/system.windows.forms.form.transparencykey.aspx" rel="nofollow noreferrer"><code>TransparencyKey</code> property</a> was set to some strange value. After clearing it altogether, it works like a charm:</p>
  
  <p><img src="https://i.stack.imgur.com/1GkKk.png" alt="Correct display"></p>