MainWindow.xaml

<Window x:Class="PMTaskbar.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:s="clr-namespace:System;assembly=System.Private.CoreLib"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:PMTaskbar"
        mc:Ignorable="d"
        x:Name="me"
        Title="" Height="480" Width="60" WindowStyle="ToolWindow" ResizeMode="NoResize" Topmost="True">
    <Window.Resources>
        <Style TargetType="{x:Type Button}">
            <Setter Property="Background" Value="DimGray"/>
            <Setter Property="BorderBrush" Value="Gray"/>
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="ButtonBase">
                        <Border BorderThickness="{TemplateBinding Border.BorderThickness}" BorderBrush="{TemplateBinding Border.BorderBrush}" CornerRadius="2" Background="{TemplateBinding Panel.Background}" Name="border" SnapsToDevicePixels="True">
                            <ContentPresenter RecognizesAccessKey="True" Content="{TemplateBinding ContentControl.Content}" ContentTemplate="{TemplateBinding ContentControl.ContentTemplate}" ContentStringFormat="{TemplateBinding ContentControl.ContentStringFormat}" Name="contentPresenter" Margin="{TemplateBinding Control.Padding}" HorizontalAlignment="{TemplateBinding Control.HorizontalContentAlignment}" VerticalAlignment="{TemplateBinding Control.VerticalContentAlignment}" SnapsToDevicePixels="{TemplateBinding UIElement.SnapsToDevicePixels}" Focusable="False" />
                        </Border>
                        <ControlTemplate.Triggers>
                            <Trigger Property="Button.IsDefaulted" Value="True">
                                <Setter Property="Border.BorderBrush" TargetName="border" Value="Gray"/>
                                <!--<Setter.Value><DynamicResource ResourceKey="{x:Static SystemColors.HighlightBrushKey}" /></Setter.Value>-->
                            </Trigger>
                            <Trigger Property="UIElement.IsMouseOver" Value="True">
                                <Setter Property="Panel.Background" TargetName="border" Value="Gray"/>
                                <Setter Property="Border.BorderBrush" TargetName="border" Value="Gray"/>
                            </Trigger>
                            <Trigger Property="ButtonBase.IsPressed" Value="True">
                                <Setter Property="Panel.Background" TargetName="border" Value="Gray"/>
                                <Setter Property="Border.BorderBrush" TargetName="border" Value="Gray"/>
                            </Trigger>
                        </ControlTemplate.Triggers>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
    </Window.Resources>

    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="*"/>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
        </Grid.RowDefinitions>

        <ListView x:Name="lst" ItemsSource="{Binding Items}" AllowDrop="True" Background="#1d2951" Drop="ListView_Drop" Grid.Row="0" BorderThickness="0"
                  ScrollViewer.VerticalScrollBarVisibility="Hidden" ScrollViewer.HorizontalScrollBarVisibility="Disabled" 
                  MouseDoubleClick="lst_MouseDoubleClick" SelectionMode="Single">
            <ListView.ContextMenu>
                <ContextMenu>
                    <ContextMenu.Style>
                        <Style TargetType="{x:Type ContextMenu}">
                            <Setter Property="Background" Value="DimGray"/>
                            <Setter Property="Foreground" Value="White"/>
                            <Setter Property="Template">
                                <Setter.Value>
                                    <ControlTemplate TargetType="{x:Type ContextMenu}">
                                        <Border BorderThickness="1" CornerRadius="4" BorderBrush="Black" x:Name="Border" Background="DimGray">
                                            <StackPanel ClipToBounds="True" Orientation="Vertical" IsItemsHost="True" />
                                        </Border>
                                        <ControlTemplate.Triggers>
                                            <Trigger Property="IsMouseOver" Value="true">
                                                <Setter TargetName="Border" Property="Background" Value="DimGray" />
                                            </Trigger>
                                        </ControlTemplate.Triggers>
                                    </ControlTemplate>
                                </Setter.Value>
                            </Setter>
                        </Style>
                    </ContextMenu.Style>
                    <MenuItem Header="Unpin" Click="UnpinMenuItem_Click" IsCheckable="False" Height="32"></MenuItem>
                </ContextMenu>
            </ListView.ContextMenu>
            <ListView.ItemContainerStyle>
                <Style TargetType="ListViewItem">
                    <Setter Property="AllowDrop" Value="True"/>
                    <EventSetter Event="PreviewMouseLeftButtonDown" Handler="ListView_MouseDown" />
                    <EventSetter Event="Drop" Handler="ListItem_Drop" />
                    <EventSetter Event="MouseEnter" Handler="ListViewItem_MouseEnter" />
                    <EventSetter Event="MouseLeave" Handler="ListViewItem_MouseLeave" />
                </Style>
            </ListView.ItemContainerStyle>
            <ListView.ItemTemplate>
                <DataTemplate>
                    <StackPanel HorizontalAlignment="Center">
                        <Image Source="{Binding IconImg}" Margin="2,4" />
                        <Popup PlacementTarget="{Binding .}" Placement="{Binding PopupPlacement,ElementName=me}" IsOpen="{Binding IsPopupShow}">
                            <ListView ItemsSource="{Binding Windows}" SelectionMode="Single" Background="DimGray" BorderThickness="0" BorderBrush="Black" HorizontalContentAlignment="Stretch">
                                <ListBox.ItemTemplate>
                                    <DataTemplate>
                                        <Border Background="DimGray" CornerRadius="2,2,0,0" ClipToBounds="False" ToolTip="{Binding Title}">
                                            <Border.Resources>
                                                <Style TargetType="ToolTip" BasedOn="{StaticResource {x:Type ToolTip}}">
                                                    <Setter Property="Foreground" Value="White" />
                                                    <Setter Property="Background" Value="#3d3d3d" />
                                                    <Setter Property="BorderBrush" Value="White" />
                                                    <Setter Property="MaxWidth" Value="50" />
                                                    <Setter Property="ContentTemplate">
                                                        <Setter.Value>
                                                            <DataTemplate>
                                                                <ContentPresenter Content="{TemplateBinding Content}">
                                                                    <ContentPresenter.Resources>
                                                                        <Style TargetType="{x:Type TextBlock}">
                                                                            <Setter Property="TextWrapping" Value="Wrap" />
                                                                        </Style>
                                                                    </ContentPresenter.Resources>
                                                                </ContentPresenter>
                                                            </DataTemplate>
                                                        </Setter.Value>
                                                    </Setter>
                                                </Style>
                                            </Border.Resources>
                                            <Grid>
                                                <Grid.ColumnDefinitions>
                                                    <ColumnDefinition Width="*"/>
                                                    <ColumnDefinition Width="Auto"/>
                                                </Grid.ColumnDefinitions>
                                                
                                                <Button HorizontalAlignment="Stretch" Click="WindowRestoreButton_Click" Foreground="White" BorderThickness="0">
                                                    <Image Source="{Binding ImgSrc}" Margin="5" />
                                                    <!--<TextBlock VerticalAlignment="Center" HorizontalAlignment="Center">
                                                        <TextBlock.Text>
                                                            <MultiBinding StringFormat="{}{0} : {1}">
                                                                <Binding Path="process.Id" />
                                                                <Binding Path="process.ProcessName" />
                                                            </MultiBinding>
                                                        </TextBlock.Text>
                                                    </TextBlock>-->
                                                </Button>

                                                <Button Width="30" Height="30" Click="WindowCloseButton_Click" Grid.Column="1" Margin="2,2,-2,0" VerticalAlignment="Top">
                                                    <Path Data="M0,0 L10,10 M10,0 L0,10" Stroke="White" />
                                                </Button>

                                            </Grid>
                                        </Border>
                                    </DataTemplate>
                                </ListBox.ItemTemplate>
                            </ListView>
                        </Popup>
                    </StackPanel>
                </DataTemplate>
            </ListView.ItemTemplate>
        </ListView>

        <StackPanel Orientation="Horizontal" Grid.Row="1" VerticalAlignment="Center" HorizontalAlignment="Center" Margin="-2,3,-2,0">
            <Button Click="UpButton_Click" Padding="5,4" Margin="0" Background="#3d3d3d">
                <Path Height="10" Width="10" Data="M 0,10 5,0 10,10 Z" StrokeThickness="0" Fill="White" Margin="0,0,0,1" />
            </Button>
            <Button Click="DnButton_Click" Padding="5,4" Margin="0" Background="#3d3d3d">
                <Path Height="10" Width="10" Data="M 0,0 5,10 10,0 Z" StrokeThickness="0" Fill="White" Margin="0,2,0,0" />
            </Button>
        </StackPanel>

        <local:TaskbarPanel ShowSeconds="{Binding PanelShowSeconds, Mode=TwoWay}" ShowDate="{Binding PanelShowDate, Mode=TwoWay}" Grid.Row="2" VerticalAlignment="Center" Margin="-2,2,-2,4" />
    </Grid>
</Window>