WPF

<Style TargetType="{x:Type TabItem}">
    <Setter Property="HeaderTemplate">
        <Setter.Value>
            <DataTemplate >
                <Grid HorizontalAlignment="Stretch" Height="22">
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="Auto" />
                        <ColumnDefinition Width="20" />
                    </Grid.ColumnDefinitions>
                    <Grid.RowDefinitions>
                        <RowDefinition Height="2"  ></RowDefinition>
                        <RowDefinition Height="Auto" ></RowDefinition>
                    </Grid.RowDefinitions>
                    <TextBlock Grid.Row="1" Text="{Binding RelativeSource={RelativeSource AncestorType={x:Type TabItem} }, Path=Header}"
                                VerticalAlignment="Bottom" Margin="4,0,8,0"/>
                                
                    <Button Grid.Row="1" 
                            Grid.Column="1"
                            Height="16"
                            Width="16"
                            BorderBrush="{x:Null}" Background="{x:Null}" 
                            Foreground="#FF224A71" 
                            VerticalAlignment="Center" 
                            Padding="3,0"
                            Command="{Binding CloseTabCommand}">
                                    
                        <TextBlock Text="x"
                                    VerticalAlignment="Center"
                                    HorizontalAlignment="Center"
                                    Margin="0,0,0,2"/>

                        <Button.ToolTip>
                            <controls:ToolTipEx Style="{StaticResource TooltipStyle}"
                                                HeaderText="Close"
                                                Icon="/FMG.UI.WPF;component/Media/Images/home_16.png"
                                                ContentAreaText="Closes this tab"/>


                        </Button.ToolTip>                                    
                        <Button.OpacityMask>
                            <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
                                <GradientStop Color="Black" Offset="0"/>
                                <GradientStop Color="#4BFFFFFF" Offset="1"/>
                            </LinearGradientBrush>
                        </Button.OpacityMask>
                                    
                        <i:Interaction.Triggers>
                            <i:EventTrigger EventName="Click">
                                <!--<Controls:CloseTabbedViewAction />-->
                            </i:EventTrigger>
                        </i:Interaction.Triggers>
                    </Button>
                </Grid>
            </DataTemplate>
        </Setter.Value>
    </Setter>
</Style>

private ICommand _CloseTabCommand;
public ICommand CloseTabCommand
{
    get
    {
        if (_CloseTabCommand == null)
            _CloseTabCommand = new RelayCommand(p => closeTabExecuted(), p => closeTabCanExecute());

        return _CloseTabCommand;
    }
}