MainView.xaml

<UserControl x:Class="WindowsBootscreenSimulatorPlus.MainView"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
             xmlns:local="clr-namespace:WindowsBootscreenSimulatorPlus"
             mc:Ignorable="d" Loaded="UserControl_Loaded"
             d:DesignHeight="450" d:DesignWidth="800">
    <Grid Background="White" Name="RootGrid">
        <StackPanel>
            <ComboBox Padding="10,5" Margin="10" Name="OsList" SelectedIndex="0" ItemsSource="{Binding Simulators}" SelectionChanged="OsList_SelectionChanged" />
            <StackPanel Orientation="Horizontal" Margin="10" >
                <CheckBox Name="StretchBox" Content="Stretch" Style="{StaticResource MaterialDesignCheckBox}" Margin="0,0,10,0"/>
                <CheckBox Name="FullscreenBox" Content="Fullscreen" Style="{StaticResource MaterialDesignCheckBox}" Margin="0,0,10,0"/>
                <CheckBox Name="ServerBox" Content="Server boot screen" Style="{StaticResource MaterialDesignCheckBox}" Margin="0,0,10,0" Visibility="Hidden"/>
            </StackPanel>
        </StackPanel>
        <Button Content="Simulate" HorizontalAlignment="Right" Margin="0,0,10,10" VerticalAlignment="Bottom" Height="30" Width="100" Click="Button_Click"/>
    </Grid>
</UserControl>