
    <Grid Margin="10"  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
 xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
        <Grid.RowDefinitions>
            <RowDefinition />
            <RowDefinition Height="2*"/>
        </Grid.RowDefinitions>
        <Grid.ColumnDefinitions>
            <ColumnDefinition/>
            <ColumnDefinition/>
        </Grid.ColumnDefinitions>
            <Label Grid.Row="0" Content="{Binding Path=IsChecked,  ElementName=play}" />
        <ToggleButton Grid.Row="1" x:Name="toggleButton" IsThreeState="{Binding ElementName=isTSToggleButton, Path=IsChecked}">
            <Polyline Stroke="Green" Fill="Green" Points="0,0 0,10 5,5"></Polyline>
        </ToggleButton>
        <ToggleButton Margin="20" Grid.Row="1" Grid.Column="1" Content="IsThreeState" x:Name="isTSToggleButton"/>
    </Grid>
