private void WindowKeyDown(object sender, KeyEventArgs e)
        {
            if ((e.KeyboardDevice.Modifiers & ModifierKeys.Control) == ModifierKeys.Control)
            {
                switch (e.Key)
                {
                case Key.Z:
                    _drawingManager.Undo();
                    break;

                case Key.C:
                    _drawingManager.LastRecordedBitmap.CopyImageToClipboard();
                    break;

                case Key.Y:
                    _drawingManager.Redo();
                    break;
                }
            }
        }