/// <summary>
 /// Adds a button to the set of registered buttons
 /// </summary>
 /// <param name="b">The button to add</param>
 public void AddButton(AbstractElement b)
 {
     Buttons.Add(b);
 }
 /// <summary>
 /// Adds a button to the set of registered buttons
 /// </summary>
 /// <param name="b">The button to add</param>
 public void RemoveButton(AbstractElement b)
 {
     if (Buttons.Contains(b))
         Buttons.Remove(b);
 }