How to add custom menu items to EditControl Embedded ContextMenu?

<Window.Resources>
 
<ContextMenu x:Key="contextmenu">
 
<MenuItem Header="Undo" Command="{x:Static syncfusion:EditCommands.Undo}" 
 
CommandTarget="{Binding RelativeSource={RelativeSource AncestorType={x:Type 
 
syncfusion:EditControl}}}">
 
<MenuItem.Icon>
 
<Image Source="pack://application:,,,/Syncfusion.Edit.Wpf;component/Resources/Undo.png" />
 
</MenuItem.Icon>
 
</MenuItem>
 
<MenuItem Header="Redo" Command="{x:Static syncfusion:EditCommands.Redo}" CommandTarget="{Binding 
 
RelativeSource={RelativeSource AncestorType={x:Type syncfusion:EditControl}}}">
 
<MenuItem.Icon>
 
<Image Source="pack://application:,,,/Syncfusion.Edit.Wpf;component/Resources/Redo.png" />
 
</MenuItem.Icon>
 
</MenuItem>
 
<MenuItem  Header="Cut" Command="{x:Static syncfusion:EditCommands.Cut}" CommandTarget="{Binding 
 
RelativeSource={RelativeSource AncestorType={x:Type syncfusion:EditControl}}}">
 
<MenuItem.Icon>
 
<Image Source="pack://application:,,,/Syncfusion.Edit.Wpf;component/Resources/Cut.png" />
 
</MenuItem.Icon>
 
</MenuItem>
 
<MenuItem Header="Copy" Command="{x:Static syncfusion:EditCommands.Copy}" CommandTarget="{Binding 
 
RelativeSource={RelativeSource AncestorType={x:Type syncfusion:EditControl}}}">
 
<MenuItem.Icon>
 
<Image Source="pack://application:,,,/Syncfusion.Edit.Wpf;component/Resources/Copy.png" />
 
</MenuItem.Icon>
 
</MenuItem>
 
<MenuItem Header="Paste" Command="{x:Static syncfusion:EditCommands.Paste}" CommandTarget="{Binding 
 
RelativeSource={RelativeSource AncestorType={x:Type syncfusion:EditControl}}}">
 
<MenuItem.Icon>
 
<Image Source="pack://application:,,,/Syncfusion.Edit.Wpf;component/Resources/Paste.png" />
 
</MenuItem.Icon>
 
</MenuItem>
 
<MenuItem Header="SelectAll" Command="{x:Static syncfusion:EditCommands.SelectAll}" 
 
CommandTarget="{Binding RelativeSource={RelativeSource AncestorType={x:Type 
 
syncfusion:EditControl}}}">
 
</MenuItem>
 
<MenuItem Header="Outlining">
 
<MenuItem Header="ExpandallText}" Command="{x:Static syncfusion:EditCommands.ExpandAll}" 
 
CommandTarget="{Binding RelativeSource={RelativeSource AncestorType={x:Type 
 
syncfusion:EditControl}}}">
 
</MenuItem>
 
<MenuItem Header="Collapseall" Command="{x:Static syncfusion:EditCommands.CollapseAll}" 
 
CommandTarget="{Binding RelativeSource={RelativeSource AncestorType={x:Type 
 
syncfusion:EditControl}}}">
 
</MenuItem>
 
</MenuItem>
 
<!-- Add Custom Context Menu -->
 
<MenuItem Header="Go To Definition"/>
 
<MenuItem Header="Find All References"/>
 
<MenuItem Header="Break Point"/>
 
<MenuItem Header="View Hierarchy"/>
 
<MenuItem Header="Increaseindent" Command="{x:Static syncfusion:EditCommands.IncreaseIndent}" 
 
CommandTarget="{Binding RelativeSource={RelativeSource AncestorType={x:Type 
 
syncfusion:EditControl}}}">
 
<MenuItem.Icon>
 
<Image Source="pack://application:,,,/Syncfusion.Edit.Wpf;component/Resources/IncreaseIndent.png" />
 
</MenuItem.Icon>
 
</MenuItem>
 
<MenuItem Header="Decreaseindent" Command="{x:Static syncfusion:EditCommands.DecreaseIndent}" 
 
 
CommandTarget="{Binding RelativeSource={RelativeSource AncestorType={x:Type 
 
syncfusion:EditControl}}}">
 
<MenuItem.Icon>
 
<Image Source="pack://application:,,,/Syncfusion.Edit.Wpf;component/Resources/DecreaseIndent.png" />
 
</MenuItem.Icon>
 
</MenuItem>
 
<MenuItem Header="Commentlines" Command="{x:Static syncfusion:EditCommands.CommentSelection}" 
 
CommandTarget="{Binding RelativeSource={RelativeSource AncestorType={x:Type 
 
syncfusion:EditControl}}}">
 
<MenuItem.Icon>
 
<Image Source="pack://application:,,,/Syncfusion.Edit.Wpf;component/Resources/Comment.png" 
MaxHeight="16" MaxWidth="16" />
 
</MenuItem.Icon>
 
</MenuItem>
 
<MenuItem Header="Uncommentlines" Command="{x:Static syncfusion:EditCommands.UncommentSelection}" 
 
CommandTarget="{Binding RelativeSource={RelativeSource AncestorType={x:Type 
 
syncfusion:EditControl}}}">
 
<MenuItem.Icon>
 
<Image Source="pack://application:,,,/Syncfusion.Edit.Wpf;component/Resources/Uncomment.png" 
MaxHeight="16" MaxWidth="16" />
 
</MenuItem.Icon>
 
</MenuItem>
 
</ContextMenu>
 
</Window.Resources>
 
<!-- EditControl -->
 
<syncfusion:EditControl ContextMenu="{StaticResource contextmenu}" Name="editText" 
 
Background="White" BorderBrush="Black" FontFamily="Verdana" FontSize="14" Foreground="Black" 
 
IsReadOnly="False" 
 
ShowDefaultContextMenu="False" >
          
</syncfusion:EditControl>