Hello. I have the problem . I can't catch events when user press any arrow key such as: Left, Right, Up, Down, NumPad4, NumPad6, NumPad2, NumPad8. But any other key press events I catch in my event handler:

	  private void OnDiagram_KeyDown(object sender, KeyEventArgs e)
	  {
		switch (e.Key)
		{
		    case Key.Escape:
			  ClearSelection();
			  break;
		    case Key.Left:
			  MoveSelectionLeft(5);
			  break;
		    case Key.Right:
			  MoveSelectionRight(5);
			  break;
		    case Key.Up:
			  MoveSelectionUp(5);
			  break;
		    case Key.Down:
			  MoveSelectionDown(5);
			  break;
		}
	  }
 

I suppose that the Diagram class catches these evetns. How can I switch off this feature for catching these events in my code?
The goal is moving selected nodes when user presses or toggles arrow buttons.

Thank you very much!