private void CommandBinding_Removed(RoutedCommandBinding commandBinding)
 {
     if (IsAttached)
     {
         TextArea.CommandBindings.Remove(commandBinding);
     }
 }
 private void CommandBinding_Added(RoutedCommandBinding commandBinding)
 {
     if (IsAttached)
     {
         TextArea.CommandBindings.Add(commandBinding);
     }
 }