Попробуйте это:
<GroupBox BorderThickness="0" Header="BELT WEIGHER BC#1 JETTY" HorizontalAlignment="Left" Margin="10,10,0,0" VerticalAlignment="Top" Height="193" Width="374" OpacityMask="Black" BorderBrush="#FF1864D3" FontSize="16" FontWeight="Bold">
<GroupBox.HeaderTemplate >
<DataTemplate>
<TextBlock Text="{Binding}"
Width="357" Grid.Column="0" Padding="5,3,0,0" Margin="0,0,0,0" Foreground="White" Height="33">
<TextBlock.Background>
<LinearGradientBrush EndPoint="0.5,1" MappingMode="RelativeToBoundingBox" StartPoint="0.5,0">
<GradientStop Color="White" Offset="0.968"/>
<GradientStop Color="Blue" Offset="0.828"/>
</LinearGradientBrush>
</TextBlock.Background>
</TextBlock>
</DataTemplate>
</GroupBox.HeaderTemplate>
<Border x:Name="CanvasBorder" BorderBrush="Blue" BorderThickness="1" Margin="3,0,3,0">
<Canvas Background="white" Margin="0,0,0,0" >
<Label Content="Feed Rate" Canvas.Left="10" Canvas.Top="10" FontWeight="Normal" FontSize="12"/>
<Label Content="Totalizer 1" Canvas.Left="10" Canvas.Top="35" FontWeight="Normal" FontSize="12"/>
<Label Content="Totalizer 2" Canvas.Left="10" Canvas.Top="60" FontWeight="Normal" FontSize="12" RenderTransformOrigin="0.516,1.808"/>
<Label Content="Belt Load" Canvas.Left="10" Canvas.Top="85" FontWeight="Normal" FontSize="12" RenderTransformOrigin="0.516,1.808"/>
<Label Content="Belt Speed" Canvas.Left="10" Canvas.Top="110" FontWeight="Normal" FontSize="12" RenderTransformOrigin="0.516,1.808"/>
<TextBlock x:Name="BC1_Feedrate" HorizontalAlignment="Left" TextWrapping="Wrap" Text="0.00" VerticalAlignment="Top" Background="#FFF2F2FB" Width="119" FontWeight="Bold" Height="20" TextAlignment="Right" Canvas.Left="91" Canvas.Top="13" Padding="0,0,4,0"/>
<TextBlock x:Name="BC1_Totalizer1" HorizontalAlignment="Left" TextWrapping="Wrap" Text="0.00" VerticalAlignment="Top" Background="#FFF2F2FB" Width="119" FontWeight="Bold" Height="20" TextAlignment="Right" Canvas.Left="91" Canvas.Top="38" Padding="0,0,4,0"/>
<TextBlock x:Name="BC1_Totalizer2" HorizontalAlignment="Left" TextWrapping="Wrap" Text="0.00" VerticalAlignment="Top" Background="#FFF2F2FB" Width="119" FontWeight="Bold" Height="20" TextAlignment="Right" Canvas.Left="91" Canvas.Top="63" Padding="0,0,4,0"/>
<TextBlock x:Name="BC1_BeltLoad" HorizontalAlignment="Left" TextWrapping="Wrap" Text="0.00" VerticalAlignment="Top" Background="#FFF2F2FB" Width="119" FontWeight="Bold" Height="20" TextAlignment="Right" Canvas.Left="91" Canvas.Top="88" Padding="0,0,4,0"/>
<TextBlock x:Name="BC1_BeltSpeed" HorizontalAlignment="Left" TextWrapping="Wrap" Text="0.00" VerticalAlignment="Top" Background="#FFF2F2FB" Width="119" FontWeight="Bold" Height="20" TextAlignment="Right" Canvas.Left="91" Canvas.Top="113" Padding="0,0,4,0"/>
<Label Content="ton/hour" Canvas.Left="228" Canvas.Top="10" FontWeight="Normal" FontSize="12"/>
<Label Content="ton" Canvas.Left="228" Canvas.Top="35" FontWeight="Normal" FontSize="12"/>
<Label Content="ton" Canvas.Left="228" Canvas.Top="60" FontWeight="Normal" FontSize="12" RenderTransformOrigin="0.516,1.808"/>
<Label Content="kg/meter" Canvas.Left="228" Canvas.Top="85" FontWeight="Normal" FontSize="12" RenderTransformOrigin="0.516,1.808"/>
<Label Content="meter/second" Canvas.Left="228" Canvas.Top="110" FontWeight="Normal" FontSize="12" RenderTransformOrigin="0.516,1.808"/>
</Canvas>
</Border>
</GroupBox>