How to change background color of TabControl.Header

Adding the following style in the TabControl.Resources section should do what you want.

<Style TargetType="{x:Type TabPanel}">    <Setter Property="Background" Value="Black"></Setter></Style>

If ShadeOfGrey answer does not work, you should use Grid instead of TabPanel:

<TabControl.Resources>    <Style TargetType="{x:Type Grid}">        <Setter Property="Background" Value="WhiteSmoke"/>    </Style></TabControl.Resources>

You should set the style for the TabPanel... Basically we arrange the Tabs in the TabPanel in the TabControl.

The below code will help you..

<TabControl Background="#123" TabStripPlacement="Left" HorizontalAlignment="Stretch" BorderBrush="#41020202">            <TabControl.BitmapEffect>                <DropShadowBitmapEffect Color="Black" Direction="270"/>            </TabControl.BitmapEffect>            <TabControl.Resources>                <Style TargetType="{x:Type TabPanel}">                    <Setter Property="Background" Value="Yellow"/>                </Style>                <Style TargetType="{x:Type TabItem}">                    <Setter Property="BorderThickness" Value="0"/>                    <Setter Property="Padding" Value="0" />                    <Setter Property="HeaderTemplate">                        <Setter.Value>                            <DataTemplate>                                <Border x:Name="grid" Background="Red">                                    <ContentPresenter>                                        <ContentPresenter.Content>                                            <TextBlock Margin="4" FontSize="15" Text="{TemplateBinding Content}"/>                                        </ContentPresenter.Content>                                        <ContentPresenter.LayoutTransform>                                            <RotateTransform Angle="270" />                                        </ContentPresenter.LayoutTransform>                                    </ContentPresenter>                                </Border>                                <DataTemplate.Triggers>                                    <DataTrigger Binding="{Binding RelativeSource={RelativeSource Mode=FindAncestor,AncestorType={x:Type TabItem}},Path=IsSelected}" Value="True">                                        <Setter TargetName="grid" Property="Background" Value="Green"/>                                    </DataTrigger>                                </DataTemplate.Triggers>                            </DataTemplate>                        </Setter.Value>                    </Setter>                </Style>            </TabControl.Resources>            <TabItem Header="Tab Item 1" />            <TabItem Header="Tab Item 2" />            <TabItem Header="Tab Item 3" />            <TabItem Header="Tab Item 4" />        </TabControl>