MyLittleWindow.xaml

<Grid>
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="*" />
        <ColumnDefinition Width="*" />
    </Grid.ColumnDefinitions>
    <Grid.RowDefinitions>
        <RowDefinition Height="Auto" />
        <RowDefinition Height="Auto" />
        <RowDefinition Height="Auto" />
        <RowDefinition Height="Auto" />
        <RowDefinition Height="Auto" />
    </Grid.RowDefinitions>
    <WrapPanel Grid.Row="0" Grid.Column="0">
        <CheckBox IsThreeState="False" IsChecked="{Binding Connection.ConnectionElectricityWanted}" Content="Elektriciteit" />
    </WrapPanel>
    <WrapPanel Grid.Row="0" Grid.Column="1">
        <CheckBox IsThreeState="False" IsChecked="{Binding Connection.ConnectionGasWanted}" Content="Gas" />
    </WrapPanel>
    <WrapPanel Grid.Row="1" Grid.Column="0">
        <ComboBox
            ItemsSource="{Binding Source={StaticResource utilityConnectionType},Path=DisplayNames}"
            SelectedItem="{Binding Path=Connection.ElectricityType, Converter={StaticResource utilityConnectionType}}" HorizontalContentAlignment="Stretch"
            />
    </WrapPanel>
    <WrapPanel Grid.Row="1" Grid.Column="1">
        <ComboBox
            ItemsSource="{Binding Source={StaticResource utilityConnectionType},Path=DisplayNames}"
            SelectedItem="{Binding Path=Connection.GasType, Converter={StaticResource utilityConnectionType}}" HorizontalContentAlignment="Stretch"
        />
    </WrapPanel>
</Grid>