FloatingWindow.xaml

<Window x:Class="WinMediaPie.FloatingWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:iconPacks="http://metro.mahapps.com/winfx/xaml/iconpacks"
        xmlns:local="clr-namespace:WinMediaPie"
        mc:Ignorable="d"
        Topmost="True"
        WindowStyle="None"
        ResizeMode="NoResize"
        WindowStartupLocation="Manual"
        AllowsTransparency="True"
        Title="FloatingWindow" Width="60" Height="90">
    <Grid TouchDown="TogglePie" MouseDown="TogglePie">
        <Grid.Background>
            <SolidColorBrush Color="#FFB0B0B0" Opacity="0.075"/>
        </Grid.Background>
        <Grid.Triggers>
            <EventTrigger RoutedEvent="Grid.MouseEnter">
                <BeginStoryboard>
                    <Storyboard>
                        <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.RenderTransform).(TransformGroup.Children)[0].(ScaleTransform.ScaleX)" Storyboard.TargetName="expand">
                            <EasingDoubleKeyFrame KeyTime="0:0:0.25" Value="0.9"/>
                        </DoubleAnimationUsingKeyFrames>
                        <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.RenderTransform).(TransformGroup.Children)[0].(ScaleTransform.ScaleY)" Storyboard.TargetName="expand">
                            <EasingDoubleKeyFrame KeyTime="0:0:0.25" Value="0.9"/>
                        </DoubleAnimationUsingKeyFrames>
                    </Storyboard>
                </BeginStoryboard>
            </EventTrigger>
            <EventTrigger RoutedEvent="Grid.MouseLeave">
                <BeginStoryboard>
                    <Storyboard>
                        <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.RenderTransform).(TransformGroup.Children)[0].(ScaleTransform.ScaleX)" Storyboard.TargetName="expand">
                            <EasingDoubleKeyFrame KeyTime="0:0:0.25" Value="1"/>
                        </DoubleAnimationUsingKeyFrames>
                        <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.RenderTransform).(TransformGroup.Children)[0].(ScaleTransform.ScaleY)" Storyboard.TargetName="expand">
                            <EasingDoubleKeyFrame KeyTime="0:0:0.25" Value="1"/>
                        </DoubleAnimationUsingKeyFrames>
                    </Storyboard>
                </BeginStoryboard>
            </EventTrigger>
        </Grid.Triggers>
        <iconPacks:PackIconMaterial x:Name="expand" Opacity="0.5" Width="40" Height="40" VerticalAlignment="Center" HorizontalAlignment="Center" Kind="ChevronLeft">
            <iconPacks:PackIconMaterial.RenderTransform>
                <TransformGroup>
                    <ScaleTransform/>
                    <SkewTransform/>
                    <RotateTransform/>
                    <TranslateTransform/>
                </TransformGroup>
            </iconPacks:PackIconMaterial.RenderTransform>
        </iconPacks:PackIconMaterial>
    </Grid>
    <Window.Background>
        <SolidColorBrush Color="#FFB0B0B0"
                         Opacity="0.0" />
    </Window.Background>
</Window>