textbox и SpellCheck

<Window x:Class="MyWordPad.MainWindow"
       xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
       xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
       Title="MySpellChecker" Height="331" Width="508"
       WindowStartupLocation="CenterScreen">
    <Window.CommandBindings>
        <CommandBinding Command="Open"
                   Executed="OpenCmdExecuted"
                   CanExecute="OpenCmdCanExecuted"/>
        <CommandBinding Command="Save"
                   Executed="SaveCmdExecuted"
                   CanExecute="SaveCmdCanExecuted"/>
    </Window.CommandBindings>
    <DockPanel>
        <Menu DockPanel.Dock="Top" Background="White" HorizontalAlignment="Left"
             BorderBrush="Black">
            <MenuItem Header="_File">
                <MenuItem Command="Open"/>
                <MenuItem Command="Save"/>
                <Separator/>
                <MenuItem Header="_Exit" MouseEnter="MouseEnterExitArea"
                         MouseLeave="MouseLeaveArea" Click="FileExit_Click"/>
            </MenuItem>
            <MenuItem Header="_Edit">
                <MenuItem Command="Cut"/>
                <MenuItem Command="Copy"/>
                <MenuItem Command="Paste"/>
            </MenuItem>
            <MenuItem Header="_Tools">
                <MenuItem Header="_Spelling Hints" MouseEnter="MouseEnterToolsHintsArea"
                         MouseLeave="MouseLeaveAreaToolsHintsArea" Click="ToolsSpellingHints_Click"/>
            </MenuItem>
        </Menu>
        <ToolBar Height="30" DockPanel.Dock="Top">
            <Button Content="Exit" MouseEnter="MouseEnterExitArea"
                   MouseLeave="MouseLeaveArea" Click="FileExit_Click"/>
            <Separator/>
            <Button Content="Check" MouseEnter="MouseLeaveAreaToolsHintsArea"
                   MouseLeave="MouseLeaveAreaToolsHintsArea"
                   Click="ToolsSpellingHints_Click" Cursor="Help"/>
        </ToolBar>
        <StatusBar DockPanel.Dock="Bottom" Background="Beige">
            <StatusBarItem>
                <TextBlock Name="statBarText" Text="Ready"/>
            </StatusBarItem>
        </StatusBar>
        <Grid DockPanel.Dock="Left" Background="AliceBlue">
            <Grid.ColumnDefinitions>
                <ColumnDefinition/>
                <ColumnDefinition/>
            </Grid.ColumnDefinitions>
            <GridSplitter Grid.Column="0" Width="5" Background="Gray"/>
            <StackPanel Grid.Column="0" VerticalAlignment="Stretch">
                <Label Name="lblSpellingInstructions" FontSize="14"
                      Margin="10,10,0,0" Content="Spelling Hints"/>
                <Expander Name="expanderSpelling" Header="Try These!" Margin="10,10,10,10">
                    <Label Name="lblSpellingHints" FontSize="12"/>
                </Expander>
            </StackPanel>
            <TextBox Grid.Column="1"
                    SpellCheck.IsEnabled="True"
                    AcceptsReturn="True"
                    Name="txtData" FontSize="14"
                    BorderBrush="Blue"
                    VerticalScrollBarVisibility="Auto"
                    HorizontalScrollBarVisibility="Auto" Margin="0,2,0,-2" TextChanged="txtData_TextChanged">
                In a custum menu you need to write code to add speler choices
    because everything in a custom context menu has to be added explicitly.
            </TextBox>
        </Grid>
    </DockPanel>
</Window>