title: Remove thin white box around WPF DatePickerTextBox
body: <p>I am writing a custom date picker and I am having some trouble setting the colors.</p>
  
  <p>I changed my Text box and background to be black however there is still a thin white rectangle around the TextBox. This white space gets filled up with the blue hover-over color when you mouse over the DatePickerTextBox field. Is there anyway to get rid of the whitespace?</p>
  
  <p>Heres some of my code</p>
  
  <pre><code>&lt;toolkit:DatePickerTextBox x:Name="PART_TextBox"                                                                       
       Grid.Row="0" Grid.Column="0" 
       Foreground="{StaticResource MenuForeground}"
       Background="{StaticResource MenuBackground}"
       BorderBrush="{StaticResource MenuBorder}" 
       HorizontalContentAlignment="Center"
       IsReadOnly="True"
       FontSize="12"
       FontFamily="Arial"
       HorizontalAlignment="Center"
       TextAlignment="Center"
       Focusable="False"
       FocusVisualStyle="{x:Null}"
       VerticalContentAlignment="Center" &gt;
  &lt;/toolkit:DatePickerTextBox&gt;
  </code></pre>