WPF button with spotlight under mouse

WPF style:

                <Style x:Key="SpotlightButton" TargetType="{x:Type Button}">
                <Setter Property="Background" Value="Transparent"/>
                <Setter Property="BorderThickness" Value="0"/>
                <Setter Property="BorderBrush" Value="Transparent"/>
                <Setter Property="Height" Value="40"/>
                <Setter Property="Foreground" Value="WhiteSmoke"/>
                <Setter Property="FontSize" Value="16"/>
                <Setter Property="Template">
                    <Setter.Value>
                        <ControlTemplate TargetType="{x:Type Button}">
                            <Border Background="{TemplateBinding BorderBrush}">
                                <Grid ClipToBounds="True" MouseMove="MoveMouseSpotLight">
                                    <ContentPresenter HorizontalAlignment="Center" VerticalAlignment="Center"/>
                                    <Grid Opacity="0" x:Name="mouseTracker" Margin="-250,-250,0,0" Width="500" Height="500" VerticalAlignment="Top" HorizontalAlignment="Left" RenderTransformOrigin="0.5,0.5">
                                        <Grid.Background>
                                            <RadialGradientBrush x:Name="gradRadial" RadiusX="0.45" RadiusY="0.45">
                                                <GradientStop Color="#33FFFFFF" Offset="0.0"/>
                                                <GradientStop Color="#00000000" Offset="1.0"/>
                                            </RadialGradientBrush>
                                        </Grid.Background>
                                        <Grid.RenderTransform>
                                            <TranslateTransform X="0" Y="0"/>
                                        </Grid.RenderTransform>
                                    </Grid>
                                </Grid>
                            </Border>
                            <ControlTemplate.Triggers>
                                <Trigger Property="IsMouseOver" Value="True">
                                    <Trigger.EnterActions>
                                        <BeginStoryboard>
                                            <Storyboard>
                                                <DoubleAnimation Storyboard.TargetName="mouseTracker" Storyboard.TargetProperty="Opacity" To="1" Duration="0:0:0.3" />
                                            </Storyboard>
                                        </BeginStoryboard>
                                    </Trigger.EnterActions>
                                    <Trigger.ExitActions>
                                        <BeginStoryboard>
                                            <Storyboard>
                                                <DoubleAnimation Storyboard.TargetName="mouseTracker" Storyboard.TargetProperty="Opacity" To="0" Duration="0:0:0.3" />
                                            </Storyboard>
                                        </BeginStoryboard>
                                    </Trigger.ExitActions>
                                </Trigger>
                                <Trigger Property="IsPressed" Value="True">
                                    <Setter Property="Background" Value="#33FFFFFF"/>
                                </Trigger>
                            </ControlTemplate.Triggers>
                        </ControlTemplate>
                    </Setter.Value>
                </Setter>
            </Style>

Mouse event here:

/// <summary>
/// Move button spotlight around
/// </summary>
/// <param name="sender">Grid from control template</param>
/// <param name="e">Mouse event</param>
private void MoveMouseSpotLight(object sender, MouseEventArgs e)
{
    try
    {
        DependencyObject light = LogicalTreeHelper.FindLogicalNode((Grid)sender, "mouseTracker");
        Point mouse = Mouse.GetPosition((Grid)sender);
        light.SetValue(FrameworkElement.RenderTransformProperty, new TranslateTransform(mouse.X, mouse.Y));
    }
    catch (Exception ex)
    {
        ex.ToString();
    }
}