OK, so I got it working.In xaml:<Button Style="{StaticResource CloseButton}" Height="16" Width="16" HorizontalAlignment="Left" Margin="282,5,0,0" Name="CloseButton" VerticalAlignment="Top" Click="CloseButton_Click"/>
In xaml.vb:Private Sub CloseButton_Click(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs)
IdentifyResultsPanel.Visibility = Visibility.Collapsed
End Sub
In App.xaml:<Application.Resources>
<!-- CloseButton Style -->
<Style x:Key="CloseButton" TargetType="Button">
<Setter Property="Width" Value="30" />
<Setter Property="Height" Value="12" />
<Setter Property="HorizontalAlignment" Value="Left" />
<Setter Property="VerticalAlignment" Value="Top" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="Button">
<Border Width="12" Height="12" CornerRadius="0,0,3,3">
<TextBlock
Foreground="WhiteSmoke"
Text="r"
FontSize="10"
FontFamily="Webdings"
TextAlignment="Center"
VerticalAlignment="Center"
>
</TextBlock>
<Border.Background>
<LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
<GradientStop Color="#FFDB9F96" Offset="0"/>
<GradientStop Color="#FFBE6D5F" Offset="0.499"/>
<GradientStop Color="#FFA63A29" Offset="0.5"/>
<GradientStop Color="#FFbE6E5A" Offset="1"/>
</LinearGradientBrush>
</Border.Background>
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</Application.Resources>