Updating a form when controls are added through a collection

public partial class DynamicForm : Form
{
    #region Zone Collection Class
    /// <summary>
    /// Zone collection class.
    /// </summary>
    public class ZoneItems : CollectionBase
    {
        #region Constructor
        // Define in here!
        #endregion

        #region Methods
        /// <summary>
        /// Gets or sets a zone by index.
        /// </summary>
        /// <param name="index">int: index of zone.</param>
        /// <returns>ZonePanel: zone at index.</returns>
        public ZonePanel this[int index]
        {
            get { return ((ZonePanel)List[index]); }
            set { List[index] = value; }
        }
        /// <summary>
        /// Adds a zone to the collection.
        /// </summary>
        /// <param name="zone">ZonePanel: zone to add.</param>
        public void Add(ZonePanel zone)
        {
            List.Add(zone);
            // Raise the zone added event.
            this.raiseZoneAddedEvent(new EventArgs());
        }
        #endregion

        #region Events
        // Create an event delegate and an event.
        public delegate void ZoneAddedEventHandler(object sender, EventArgs e);
        /// <summary>
        /// Occurs when a zone is added.
        /// </summary>
        public event ZoneAddedEventHandler ZoneAdded;
        // Wrap raising the event in a method.
        protected void raiseZoneAddedEvent(EventArgs e)
        {
            if (ZoneAdded != null)
            {
                ZoneAdded(this, e);
            }
        }
        #endregion
    }
    #endregion
}

public partial class DynamicForm : Form
{

// Property related fields.
protected ZoneItems pZoneRegion;

...

#region Event Handlers
// Handle the items zone added event handler.
protected virtual void Items_ZoneAdded(object sender, EventArgs e)
{
    // Add the zone to the forms control collection.
    this.Controls.Add(((ZoneItems)sender)[((ZoneItems)sender).Count - 1]);
}
#endregion


...


#region Properties
/// <summary>
/// Gets or sets the zone control collection.
/// </summary>
[Category("Design")]
[Description("Adds zone regions to the forms zone collection.")]
// Must serialize contents of the panel since it holds controls.
[DesignerSerializationVisibility(DesignerSerializationVisibility.Content)]
public virtual ZoneItems ZoneRegion
{
    get
    {
        return this.pZoneRegion;
    }
    set
    {
        this.pZoneRegion = value;
    }
}
#endregion


}