MVVMLight Using Two Views

<Window x:Class="MvvmLightTest.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="Mvvm Light Example"
        Width="525"
        Height="350"
        DataContext="{Binding Main,
                              Source={StaticResource Locator}}"
        ResizeMode="NoResize"
        SizeToContent="WidthAndHeight">
    <Grid>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="Auto" />
            <ColumnDefinition Width="Auto" />
        </Grid.ColumnDefinitions>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto" />
            <RowDefinition Height="Auto" />
            <RowDefinition Height="257*" />
        </Grid.RowDefinitions>
        <Button Command="{Binding ShowPopUp}" Content="Show Pop Up" />
        <Button Grid.Row="1"
                Command="{Binding IncrementValue}"
                Content="Increment value" />
        <TextBlock Grid.Row="1"
                   Grid.Column="1"
                   MinWidth="50"
                   HorizontalAlignment="Center"
                   VerticalAlignment="Center"
                   Text="{Binding ExampleValue}"
                   TextAlignment="Center" />
    </Grid>
</Window>