Proper Style Inheritance in WPF

App.xaml

<Application x:Class="WpfApplication1.App"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:controls="clr-namespace:WpfApplication1.Controls"
             StartupUri="MainWindow.xaml">
    <Application.Resources>
        <Style TargetType="{x:Type Control}" x:Key="MetroControl">
            <Setter Property="Foreground" Value="{Binding RelativeSource={RelativeSource AncestorType={x:Type FrameworkElement}}, Path=(TextElement.Foreground)}"/>
        </Style>
        <Style TargetType="{x:Type Label}" BasedOn="{StaticResource MetroControl}"/>
        <Style TargetType="{x:Type Button}" BasedOn="{StaticResource MetroControl}"/>
        <Style TargetType="{x:Type controls:CircleButton}" BasedOn="{StaticResource MetroControl}"/>
        <Style TargetType="{x:Type Window}" BasedOn="{StaticResource MetroControl}" x:Key="MetroWindow">
            <Setter Property="Foreground" Value="Red"/>
            <Setter Property="FontFamily" Value="arial"/>
            <Setter Property="FontWeight" Value="Bold"/>
        </Style>
        <Style TargetType="{x:Type Window}" BasedOn="{StaticResource MetroWindow}"/>
    </Application.Resources>
</Application>

CircleButton.xaml

<Button x:Class="WpfApplication1.Controls.CircleButton"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
             mc:Ignorable="d" 
             d:DesignHeight="300" d:DesignWidth="300">
    <Button.Template>
        <ControlTemplate>
            <Grid  Width="50" Height="50" Background="Green">
                <TextBlock Text="T" HorizontalAlignment="Center" VerticalAlignment="Center"/>
            </Grid>            
        </ControlTemplate>
    </Button.Template>
</Button>

MainWindow.xaml

<Window x:Class="WpfApplication1.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:controls="clr-namespace:WpfApplication1.Controls"
        xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"
        xmlns:attachedProperties="clr-namespace:WpfApplication1.AttachedProperties"
        Title="MainWindow" Height="350" Width="525" Style="{StaticResource MetroWindow}">
    <StackPanel>
        <Label Content="Test Label"/>
        <Button Content="Test Button"/>
        <TextBlock Text="Test TextBlock" Background="BlueViolet"/>
        <controls:CircleButton Click="ButtonBase_OnClick">
            <i:Interaction.Behaviors>
                <attachedProperties:PopupButtonTestBehavior PopupPlacement="MousePoint" PopupHorizontalOffset="20">
                    <attachedProperties:PopupButtonTestBehavior.Popup>
                        <StackPanel Width="100" Height="100" Background="Black">
                            <TextBlock Text="Textblock"/>
                            <Label Content="Label"/>
                            <Button Content="Button"/>
                        </StackPanel>
                    </attachedProperties:PopupButtonTestBehavior.Popup>
                </attachedProperties:PopupButtonTestBehavior>
            </i:Interaction.Behaviors>
        </controls:CircleButton>
    </StackPanel>
</Window>