title: ComboBox remove blue underline
body: <p>I have language <code>ComboBox</code> which works perfect, but after clicking to change the language then this weird blue underline appears. I'm not quite sure where this comes from</p>
  <p><a href="https://i.stack.imgur.com/ztTuE.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/ztTuE.png" alt="Language ComboBox with a selected item that is underlined." /></a></p>
  <pre><code>&lt;ComboBox ItemsSource=&quot;{Binding SupportedLanguages, Mode=OneTime}&quot;
                  Name=&quot;LanguageComboBox&quot;
                  Padding=&quot;2&quot;
                  BorderThickness=&quot;0&quot;
                  BorderBrush=&quot;Transparent&quot;
                  HorizontalAlignment=&quot;Right&quot;
                  SelectedItem=&quot;{Binding SelectedLanguageName}&quot; 
                  Background=&quot;Transparent&quot;
                  UseLayoutRounding=&quot;True&quot;&gt;
      &lt;ComboBox.ItemTemplate&gt;
          &lt;DataTemplate DataType=&quot;model:CountryFlagDto&quot;&gt;
              &lt;StackPanel Orientation=&quot;Horizontal&quot;&gt;
                  &lt;Image Source=&quot;{Binding Path=LangKey, Converter={StaticResource CountryIdToFlagImageSourceConverter}}&quot;
                              Width=&quot;23&quot; Height=&quot;34&quot;  RenderOptions.BitmapScalingMode=&quot;HighQuality&quot; /&gt;
              &lt;/StackPanel&gt;
          &lt;/DataTemplate&gt;
      &lt;/ComboBox.ItemTemplate&gt;
  &lt;/ComboBox&gt;
  </code></pre>