sourcegit/src/Views/LauncherPage.axaml

<UserControl xmlns="https://github.com/avaloniaui"
             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:m="using:SourceGit.Models"
             xmlns:v="using:SourceGit.Views"
             xmlns:vm="using:SourceGit.ViewModels"
             xmlns:c="using:SourceGit.Converters"
             mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
             x:Class="SourceGit.Views.LauncherPage"
             x:DataType="vm:LauncherPage">
  <Grid RowDefinitions="36,*">
    <!-- ToolBar -->
    <Border Grid.Row="0" BorderBrush="{DynamicResource Brush.Border0}" BorderThickness="0,0,0,1" Background="{DynamicResource Brush.ToolBar}">
      <ContentControl Content="{Binding Data}">
        <ContentControl.DataTemplates>
          <DataTemplate DataType="vm:Welcome">
            <v:WelcomeToolbar/>
          </DataTemplate>
          
          <DataTemplate DataType="vm:Repository">
            <v:RepositoryToolbar/>
          </DataTemplate>
        </ContentControl.DataTemplates>
      </ContentControl>
    </Border>
    
    <!-- Body -->
    <Border Grid.Row="1">
      <ContentControl Content="{Binding Data}">
        <ContentControl.DataTemplates>
          <DataTemplate DataType="vm:Welcome">
            <v:Welcome/>
          </DataTemplate>
          
          <DataTemplate DataType="vm:Repository">
            <v:Repository/>
          </DataTemplate>
        </ContentControl.DataTemplates>
      </ContentControl>
    </Border>

    <!-- Floating -->
    <Grid Grid.Row="1" ClipToBounds="True">
      <Grid.IsVisible>
        <MultiBinding Converter="{x:Static BoolConverters.Or}">
          <Binding Path="Popup" Converter="{x:Static ObjectConverters.IsNotNull}"/>
          <Binding Path="Notifications.Count" Converter="{x:Static c:IntConverters.IsGreaterThanZero}"/>
        </MultiBinding>
      </Grid.IsVisible>

      <Border Background="Transparent"
              PointerPressed="OnMaskClicked"
              IsVisible="{Binding Popup, Converter={x:Static ObjectConverters.IsNotNull}}"/>

      <Grid RowDefinitions="Auto,*" Width="512" HorizontalAlignment="Center">
        <!-- Popup -->
        <Border Grid.Row="0"
                Margin="6,0"
                Effect="drop-shadow(0 0 8 #8F000000)"
                CornerRadius="0,0,8,8"
                ClipToBounds="True"
                IsVisible="{Binding Popup, Converter={x:Static ObjectConverters.IsNotNull}}">
          <ContentControl Content="{Binding Popup}" Background="{DynamicResource Brush.Popup}">
            <ContentControl.DataTemplates>
              <DataTemplate DataType="vm:Popup">
                <StackPanel Orientation="Vertical" Background="{DynamicResource Brush.Popup}">
                  <!-- Popup Widget -->
                  <ContentPresenter Margin="8,16,8,8"
                                    Content="{Binding View}"
                                    IsHitTestVisible="{Binding InProgress, Converter={x:Static BoolConverters.Not}}"/>

                  <!-- Options -->
                  <StackPanel Margin="8,4,8,8"
                              Height="32"
                              Orientation="Horizontal"
                              HorizontalAlignment="Right"
                              IsVisible="{Binding InProgress, Converter={x:Static BoolConverters.Not}}">
                    <Button Classes="flat primary"
                            Width="80" Height="28"
                            Padding="0"
                            HorizontalContentAlignment="Center"
                            VerticalContentAlignment="Center"
                            Content="{DynamicResource Text.Sure}"
                            Click="OnPopupSure"
                            HotKey="Enter"/>
                    <Button Classes="flat"
                            Width="80" Height="28"
                            Margin="8,0,0,0"
                            Padding="0"
                            HorizontalContentAlignment="Center"
                            VerticalContentAlignment="Center"
                            Content="{DynamicResource Text.Cancel}"
                            Click="OnPopupCancel"/>
                  </StackPanel>

                  <!-- Running -->
                  <v:PopupRunningStatus Margin="12,8"
                                        Description="{Binding ProgressDescription}"
                                        IsVisible="{Binding InProgress}"/>
                </StackPanel>
              </DataTemplate>
            </ContentControl.DataTemplates>
          </ContentControl>
        </Border>

        <!-- Notifications -->
        <ScrollViewer Grid.Row="1" Margin="0,6,0,0" VerticalAlignment="Top" HorizontalScrollBarVisibility="Disabled" VerticalScrollBarVisibility="Auto">
          <ItemsControl ItemsSource="{Binding Notifications}">
            <ItemsControl.ItemTemplate>
              <DataTemplate DataType="m:Notification">
                <Border Margin="6" HorizontalAlignment="Stretch" VerticalAlignment="Top" Effect="drop-shadow(0 0 8 #8F000000)">
                  <Border Padding="8" CornerRadius="6" Background="{DynamicResource Brush.Popup}">
                    <Grid RowDefinitions="26,Auto">
                      <Grid Grid.Row="0" ColumnDefinitions="Auto,*,Auto" Margin="8,0">
                        <Path Grid.Column="0" Width="14" Height="14" Data="{StaticResource Icons.Error}" Fill="Red" IsVisible="{Binding IsError}"/>
                        <Path Grid.Column="0" Width="14" Height="14" Data="{StaticResource Icons.Info}" Fill="Green" IsVisible="{Binding !IsError}"/>
                        <TextBlock Grid.Column="1" Margin="8,0,0,0" FontWeight="Bold" FontSize="14" Text="{DynamicResource Text.Launcher.Error}" IsVisible="{Binding IsError}"/>
                        <TextBlock Grid.Column="1" Margin="8,0,0,0" FontWeight="Bold" FontSize="14" Text="{DynamicResource Text.Launcher.Info}" IsVisible="{Binding !IsError}"/>
                        <Button Grid.Column="2" Classes="icon_button" Width="16" Height="16" Click="OnDismissNotification">
                          <Path Width="10" Height="10" Data="{StaticResource Icons.Window.Close}"/>
                        </Button> 
                      </Grid>

                      <ScrollViewer Grid.Row="1" Margin="8" MaxHeight="100" HorizontalScrollBarVisibility="Disabled" VerticalScrollBarVisibility="Auto">
                        <SelectableTextBlock TextWrapping="Wrap" Text="{Binding Message}"/>
                      </ScrollViewer>
                    </Grid>
                  </Border>
                </Border>
              </DataTemplate>
            </ItemsControl.ItemTemplate>
          </ItemsControl>
        </ScrollViewer>
      </Grid>
    </Grid>
  </Grid>
</UserControl>