Hourglass Mouse Cursor Always Changes Back to its Original Image. How?

public sealed class WaitCursor : IDisposable
{
  private Cursor _SavedCursor;
  public WaitCursor()
  {
    _SavedCursor = Cursor.Current;
    Cursor.Current = Cursors.WaitCursor;
  }
  public void Dispose()
  {
    Cursor.Current = _SavedCursor;
  }
}

using (new WaitCursor())
{
  // do something
}