GARbro-crskycode/ArcFormats/LiveMaker/WidgetGAL.xaml

<StackPanel x:Class="GameRes.Formats.GUI.WidgetGAL"
      xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
      xmlns:s="clr-namespace:GameRes.Formats.Strings"
      xmlns:p="clr-namespace:GameRes.Formats.Properties"
      xmlns:local="clr-namespace:GameRes.Formats.GUI"
      MaxWidth="250" Orientation="Vertical">
    <StackPanel.Resources>
        <local:GaleKeyConverter x:Key="keyConverter"/>
        <Style TargetType="{x:Type TextBox}">
            <Style.Triggers>
                <Trigger Property="Validation.HasError" Value="true">
                    <Setter Property="ToolTip"
                            Value="{Binding RelativeSource={RelativeSource Self}, Path=(Validation.Errors)[0].ErrorContent}"/>
                </Trigger>
            </Style.Triggers>
        </Style>
    </StackPanel.Resources>
    <Label HorizontalAlignment="Left" Margin="0,0,5,5" Padding="0">
         <TextBlock Text="{x:Static s:arcStrings.GALChoose}" TextWrapping="WrapWithOverflow"/>
    </Label>
    <ComboBox Name="Title" ItemsSource="{Binding}"
              SelectedValue="{Binding ElementName=Key, Path=Text, Converter={StaticResource keyConverter}}"
              SelectedValuePath="Value" DisplayMemberPath="Key"
              Width="200" HorizontalAlignment="Left"/>
    <TextBox Name="Key" Width="200" HorizontalAlignment="Left" Margin="0,5,0,0">
        <TextBox.Text>
            <Binding Source="{x:Static p:Settings.Default}" Path="GALKey" Mode="TwoWay" UpdateSourceTrigger="PropertyChanged" Converter="{StaticResource keyConverter}">
                <Binding.ValidationRules>
                    <local:GaleKeyRule/>
                </Binding.ValidationRules>                            
            </Binding>
        </TextBox.Text>
        <Validation.ErrorTemplate>
            <ControlTemplate>
                <DockPanel>
                    <TextBlock DockPanel.Dock="Right" Foreground="Red" FontWeight="Bold" Text="!" VerticalAlignment="Center"/>
                    <Border BorderBrush="Red" BorderThickness="1">
                        <AdornedElementPlaceholder Name="ValidationAdorner" />
                    </Border>
                </DockPanel>
            </ControlTemplate>
        </Validation.ErrorTemplate>
    </TextBox>
</StackPanel>