Waveform.xaml

<UserControl x:Class="CSCoreWaveform.Waveform"
             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"
             >
    <Grid>
        <Canvas x:Name="PART_Canvas" VerticalAlignment="Stretch" HorizontalAlignment="Stretch" 
                MouseLeftButtonDown="PART_Canvas_OnMouseLeftButtonDown">
            <Path Name="PART_Path">
                <Path.Style>
                    <Style TargetType="Path">
                        <Setter Property="Fill" Value="Green"/>
                        <Setter Property="Stroke" Value="Transparent"/>
                        <Style.Triggers>
                            <DataTrigger Binding="{Binding IsMouseOver, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Canvas}}}" Value="True">
                                <Setter Property="Fill" Value="DarkGreen"/>
                            </DataTrigger>
                        </Style.Triggers>
                    </Style>
                </Path.Style>
            </Path>
        </Canvas>
    </Grid>
</UserControl>