BeWoPlaner/BeWo/MainWindow.xaml

<Window x:Class="BeWo.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="BeWoPlaner" Height="768" Width="1024" WindowStartupLocation="CenterScreen" WindowState="Maximized"
              BorderThickness="1" Closing="MainWindow_OnClosing" SizeChanged="Window_SizeChanged">
    <Grid x:Name="rootGrid">
        <ComboBox Width="100"></ComboBox>
    </Grid>
</Window>