MainWindow.xaml

<Window
    x:Class="WinUI3_NotifyIcon.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:WinUI3_NotifyIcon"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d">
  
     <Grid>

        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="200"></ColumnDefinition>           
            <ColumnDefinition Width="*"></ColumnDefinition>
            <!--<ColumnDefinition Width="100"></ColumnDefinition>-->
        </Grid.ColumnDefinitions>
        <Grid.RowDefinitions>
            <RowDefinition Height="200"></RowDefinition>
            <RowDefinition Height="*"></RowDefinition>
        </Grid.RowDefinitions>

        <StackPanel Orientation="Vertical" Grid.Row="0" Grid.Column="0">
            <!--<Button x:Name="myButton" Click="myButton_Click" Margin="10, 10, 0, 0"
                 HorizontalAlignment="Left">
             Minimize to Tray
         </Button>-->
            <Button x:Name="myButton" Click="myButton_Click" HorizontalAlignment="Center" VerticalAlignment="Top" Width="66" Height="54" Margin="10, 10, 10, 0"
                 FontFamily="Segoe UI Emoji" FontSize="46" Content="&#x1F4E5;" Padding="0, -12, 0, 0">
                <ToolTipService.ToolTip>
                    <ToolTip Content="Minimize to Tray" Placement="Bottom" Background="LightYellow" Foreground="Black"/>
                </ToolTipService.ToolTip>
            </Button>
            <ToggleSwitch Grid.Column="1" x:Name="tsNotify" Margin="20, 20, 0, 0" Header="Balloon Notification" HorizontalAlignment="Center"
                          OffContent="No" OnContent="Yes" Toggled="tsNotify_Toggled" >
            <ToolTipService.ToolTip>
                <ToolTip Content="Show Balloon Notification or not" Placement="Bottom" Background="LightYellow" Foreground="Black"/>
            </ToolTipService.ToolTip>
        </ToggleSwitch>
        </StackPanel>

        <StackPanel Orientation="Vertical" Grid.Row="0" Grid.Column="1">
            <RadioButtons Grid.Column="0" x:Name="rbContextMenu" Margin="10, 10, 0, 0" SelectedIndex="0" Header="Menu style" SelectionChanged="rbContextMenu_SelectionChanged">
                <RadioButton Content="Standard Context Menu" x:Name="rbStandard">
                    <ToolTipService.ToolTip>
                        <ToolTip Content="Use standard style &#x0a;for Context Menu in Tray icon" Placement="Bottom" Background="LightYellow" Foreground="Black"/>
                    </ToolTipService.ToolTip>
                </RadioButton>
                <RadioButton Content="Owner-Drawn Context Menu" x:Name="rbOD">
                    <ToolTipService.ToolTip>
                        <ToolTip Content="Use Owner-Drawn Menu items &#x0a;for Context Menu in Tray icon" Placement="Bottom" Background="LightYellow" Foreground="Black"/>
                    </ToolTipService.ToolTip>
                </RadioButton>              
            </RadioButtons>
        </StackPanel>          

    </Grid>
</Window>