HandyControl/src/Shared/HandyControl_Shared/Themes/Styles/Base/GroupBoxBaseStyle.xaml

<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
                    xmlns:controls="clr-namespace:HandyControl.Controls"
                    xmlns:themes="clr-namespace:HandyControl.Themes">

    <ResourceDictionary.MergedDictionaries>
        <themes:SharedResourceDictionary Source="pack://application:,,,/HandyControl;component/Themes/Basic/Sizes.xaml"/>
        <themes:SharedResourceDictionary Source="pack://application:,,,/HandyControl;component/Themes/Basic/Converters.xaml"/>
    </ResourceDictionary.MergedDictionaries>

    <ControlTemplate x:Key="GroupBoxBaseTopTemplate" TargetType="GroupBox">
        <Grid>
            <Grid.RowDefinitions>
                <RowDefinition Height="Auto" MinHeight="30"/>
                <RowDefinition/>
            </Grid.RowDefinitions>
            <Border MinHeight="30" BorderThickness="{TemplateBinding BorderThickness}" BorderBrush="{TemplateBinding BorderBrush}" Background="{Binding Path=(controls:TitleElement.Background),RelativeSource={RelativeSource TemplatedParent}}" CornerRadius="{Binding Path=(controls:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" Margin="0,0,0,6">
                <ContentPresenter TextElement.Foreground="{TemplateBinding Foreground}"  Margin="10,0" VerticalAlignment="{TemplateBinding VerticalContentAlignment}" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" ContentSource="Header" RecognizesAccessKey="True" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
            </Border>
            <Border Grid.Row="1" CornerRadius="{Binding Path=(controls:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" Background="{TemplateBinding Background}" BorderThickness="{TemplateBinding BorderThickness}" BorderBrush="{TemplateBinding BorderBrush}">
                <ContentPresenter Margin="{TemplateBinding Padding}" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
            </Border>
        </Grid>
    </ControlTemplate>

    <ControlTemplate x:Key="GroupBoxBaseLeftTemplate" TargetType="GroupBox">
        <Grid>
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="Auto" MinWidth="30"/>
                <ColumnDefinition/>
            </Grid.ColumnDefinitions>
            <Border MinWidth="30" BorderThickness="{TemplateBinding BorderThickness}" ClipToBounds="False" BorderBrush="{TemplateBinding BorderBrush}" Background="{Binding Path=(controls:TitleElement.Background),RelativeSource={RelativeSource TemplatedParent}}" CornerRadius="{Binding Path=(controls:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" Margin="0,0,6,0">
                <ContentPresenter TextElement.Foreground="{TemplateBinding Foreground}"  Margin="0,10" VerticalAlignment="{TemplateBinding VerticalContentAlignment}" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" ContentSource="Header" RecognizesAccessKey="True" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" RenderTransformOrigin="0.5,0.5">
                    <ContentPresenter.LayoutTransform>
                        <TransformGroup>
                            <RotateTransform Angle="-90"/>
                        </TransformGroup>
                    </ContentPresenter.LayoutTransform>
                </ContentPresenter>
            </Border>
            <Border Grid.Column="1" CornerRadius="{Binding Path=(controls:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" Background="{TemplateBinding Background}" BorderThickness="{TemplateBinding BorderThickness}" BorderBrush="{TemplateBinding BorderBrush}">
                <ContentPresenter Margin="{TemplateBinding Padding}" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
            </Border>
        </Grid>
    </ControlTemplate>

    <Style x:Key="GroupBoxBaseStyle" TargetType="GroupBox">
        <Setter Property="BorderBrush" Value="{DynamicResource BorderBrush}"/>
        <Setter Property="Background" Value="{DynamicResource SecondaryRegionBrush}"/>
        <Setter Property="Foreground" Value="{DynamicResource TextIconBrush}"/>
        <Setter Property="controls:TitleElement.Background" Value="{DynamicResource TitleBrush}"/>
        <Setter Property="controls:TitleElement.TitlePlacement" Value="Top"/>
        <Setter Property="controls:BorderElement.CornerRadius" Value="{StaticResource DefaultCornerRadius}"/>
        <Setter Property="VerticalContentAlignment" Value="Center"/>
        <Setter Property="HorizontalContentAlignment" Value="Center"/>
        <Setter Property="BorderThickness" Value="0"/>
        <Setter Property="Padding" Value="4"/>
        <Setter Property="Template" Value="{StaticResource GroupBoxBaseTopTemplate}"/>
        <Style.Triggers>
            <Trigger Property="controls:TitleElement.TitlePlacement" Value="Left">
                <Setter Property="Template" Value="{StaticResource GroupBoxBaseLeftTemplate}"/>
            </Trigger>
        </Style.Triggers>
    </Style>

    <ControlTemplate x:Key="GroupBoxOriginalTopTemplate" TargetType="GroupBox">
        <Grid>
            <Grid.RowDefinitions>
                <RowDefinition Height="Auto"/>
                <RowDefinition/>
            </Grid.RowDefinitions>
            <StackPanel Orientation="Horizontal" Margin="8,6">
                <ContentPresenter TextElement.Foreground="{TemplateBinding Foreground}" Margin="1,0,0,0" VerticalAlignment="{TemplateBinding VerticalContentAlignment}" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" ContentSource="Header" RecognizesAccessKey="True" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
                <ContentPresenter TextElement.Foreground="{DynamicResource DangerBrush}" Margin="4,0,0,0" Content="{Binding Path=(controls:InfoElement.Symbol),RelativeSource={RelativeSource TemplatedParent}}" Visibility="{Binding Path=(controls:InfoElement.Necessary),RelativeSource={RelativeSource TemplatedParent},Converter={StaticResource Boolean2VisibilityConverter}}"/>
            </StackPanel>
            <Border Grid.Row="1" CornerRadius="{Binding Path=(controls:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" Background="{TemplateBinding Background}" BorderThickness="{TemplateBinding BorderThickness}" BorderBrush="{TemplateBinding BorderBrush}">
                <ContentPresenter Margin="{TemplateBinding Padding}" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
            </Border>
        </Grid>
    </ControlTemplate>

    <ControlTemplate x:Key="GroupBoxOriginalLeftTemplate" TargetType="GroupBox">
        <Grid>
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="{Binding Path=(controls:InfoElement.TitleWidth),RelativeSource={RelativeSource TemplatedParent}}"/>
                <ColumnDefinition/>
            </Grid.ColumnDefinitions>
            <StackPanel Orientation="Horizontal" VerticalAlignment="{TemplateBinding VerticalContentAlignment}" Margin="0,8,6,8">
                <ContentPresenter TextElement.Foreground="{TemplateBinding Foreground}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}" ContentSource="Header" RecognizesAccessKey="True" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
                <ContentPresenter TextElement.Foreground="{DynamicResource DangerBrush}" Margin="4,0,0,0" Content="{Binding Path=(controls:InfoElement.Symbol),RelativeSource={RelativeSource TemplatedParent}}" Visibility="{Binding Path=(controls:InfoElement.Necessary),RelativeSource={RelativeSource TemplatedParent},Converter={StaticResource Boolean2VisibilityConverter}}"/>
            </StackPanel>
            <Border Grid.Column="1" CornerRadius="{Binding Path=(controls:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" Background="{TemplateBinding Background}" BorderThickness="{TemplateBinding BorderThickness}" BorderBrush="{TemplateBinding BorderBrush}">
                <ContentPresenter Margin="{TemplateBinding Padding}" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
            </Border>
        </Grid>
    </ControlTemplate>

    <Style x:Key="GroupBoxOriginalBaseStyle" BasedOn="{StaticResource GroupBoxBaseStyle}" TargetType="GroupBox">
        <Setter Property="Foreground" Value="{DynamicResource PrimaryTextBrush}"/>
        <Setter Property="controls:BorderElement.CornerRadius" Value="0"/>
        <Setter Property="VerticalContentAlignment" Value="Top"/>
        <Setter Property="Background" Value="Transparent"/>
        <Setter Property="Padding" Value="0"/>
        <Setter Property="Template" Value="{StaticResource GroupBoxOriginalTopTemplate}"/>
        <Style.Triggers>
            <Trigger Property="controls:TitleElement.TitlePlacement" Value="Left">
                <Setter Property="Template" Value="{StaticResource GroupBoxOriginalLeftTemplate}"/>
            </Trigger>
        </Style.Triggers>
    </Style>

    <ControlTemplate x:Key="GroupBoxTabTopTemplate" TargetType="GroupBox">
        <Grid>
            <Grid.RowDefinitions>
                <RowDefinition Height="Auto" MinHeight="30"/>
                <RowDefinition/>
            </Grid.RowDefinitions>
            <Border Grid.Row="1" CornerRadius="{Binding Path=(controls:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent},Converter={StaticResource CornerRadiusSplitConverter},ConverterParameter='0,0,1,1'}" Background="{TemplateBinding Background}" BorderThickness="{TemplateBinding BorderThickness}" BorderBrush="{TemplateBinding BorderBrush}">
                <ContentPresenter Margin="{TemplateBinding Padding}" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
            </Border>
            <Border Grid.Row="0" MinHeight="30" BorderThickness="{TemplateBinding BorderThickness}" BorderBrush="{TemplateBinding BorderBrush}" Background="{Binding Path=(controls:TitleElement.Background),RelativeSource={RelativeSource TemplatedParent}}" CornerRadius="4,4,0,0">
                <ContentPresenter TextElement.Foreground="{TemplateBinding Foreground}" Margin="10,0" VerticalAlignment="{TemplateBinding VerticalContentAlignment}" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" ContentSource="Header" RecognizesAccessKey="True" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
            </Border>
        </Grid>
    </ControlTemplate>

    <ControlTemplate x:Key="GroupBoxTabLeftTemplate" TargetType="GroupBox">
        <Grid>
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="Auto" MinWidth="30"/>
                <ColumnDefinition/>
            </Grid.ColumnDefinitions>
            <Border Grid.Column="1" CornerRadius="{Binding Path=(controls:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent},Converter={StaticResource CornerRadiusSplitConverter},ConverterParameter='0,1,1,0'}" Background="{TemplateBinding Background}" BorderThickness="{TemplateBinding BorderThickness}" BorderBrush="{TemplateBinding BorderBrush}">
                <ContentPresenter Margin="{TemplateBinding Padding}" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
            </Border>
            <Border Grid.Column="0" MinWidth="30" BorderThickness="{TemplateBinding BorderThickness}" BorderBrush="{TemplateBinding BorderBrush}" Background="{Binding Path=(controls:TitleElement.Background),RelativeSource={RelativeSource TemplatedParent}}" CornerRadius="4,0,0,4">
                <ContentPresenter TextElement.Foreground="{TemplateBinding Foreground}" Margin="0,10" VerticalAlignment="{TemplateBinding VerticalContentAlignment}" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" ContentSource="Header" RecognizesAccessKey="True" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}">
                    <ContentPresenter.LayoutTransform>
                        <TransformGroup>
                            <RotateTransform Angle="-90"/>
                        </TransformGroup>
                    </ContentPresenter.LayoutTransform>
                </ContentPresenter>
            </Border>
        </Grid>
    </ControlTemplate>

    <Style x:Key="GroupBoxTabBaseStyle" BasedOn="{StaticResource GroupBoxBaseStyle}" TargetType="GroupBox">
        <Setter Property="Template" Value="{StaticResource GroupBoxTabTopTemplate}"/>
        <Style.Triggers>
            <Trigger Property="controls:TitleElement.TitlePlacement" Value="Left">
                <Setter Property="Template" Value="{StaticResource GroupBoxTabLeftTemplate}"/>
            </Trigger>
        </Style.Triggers>
    </Style>

</ResourceDictionary>