PropertyGrid with ConfigurationElementCollection (cannot Add / Remove from collection)

Question

I have a ConfigurationElementCollection bound to a PropertyGrid.

The Collection properties can be viewed successful and each existing item can actually be edited without problem.

However, I cannot Add new items or Remove existing ones as the Add/Remove buttons are disabled.

There are public Add() and Remove() methods on the Collection and also a public Indexer which I thought would be sufficient.

Is there anything obvious I'm missing here.

Code is shown below:

 public class WatchConfiguration : ConfigurationSection
    {

        public WatchConfiguration()
        {

        }

        public static WatchConfiguration Current
        {
            get
            {
                return (WatchConfiguration)ConfigurationManager.GetSection("WatchConfiguration");
            }
        }

        [ConfigurationProperty("Watches", IsDefaultCollection = false), ConfigurationCollection(typeof(WatchCollection), AddItemName = "addWatch", ClearItemsName = "clearWatches", RemoveItemName = "removeWatch")]
        public WatchCollection Watches
        {
            get { return this["Watches"] as WatchCollection; }
            set { (this["Watches"] as WatchCollection).Add(new WatchElement()); }
        }

        public override bool IsReadOnly()
        {
            return false;
        }

    }



    public class WatchCollection : ConfigurationElementCollection
    {
        public override ConfigurationElementCollectionType CollectionType
        {
            get
            {
                return ConfigurationElementCollectionType.AddRemoveClearMap;
            }
        }

        public WatchElement this[int index]
        {
            get { return (WatchElement)BaseGet(index); }
            set
            {
                if (BaseGet(index) != null)
                    BaseRemoveAt(index);
                BaseAdd(index, value);
            }
        }

        public void Add(WatchElement element)
        {
            BaseAdd(element);
        }

        public void Clear()
        {
            BaseClear();
        }

        protected override ConfigurationElement CreateNewElement()
        {
            return new WatchElement();
        }

        protected override object GetElementKey(ConfigurationElement element)
        {
            return ((WatchElement)element).Epic;
        }

        public void Remove(WatchElement element)
        {
            BaseRemove(element.Epic);
        }

        public void Remove(string epic)
        {
            BaseRemove(epic);
        }

        public void RemoveAt(int index)
        {
            BaseRemoveAt(index);
        }
    }




    public class WatchElement : ConfigurationElement
    {
        public WatchElement() { }

        public WatchElement(string epic, string colour)
        {
            this.Epic = epic;
            this.Colour = colour;
        }

        public override bool IsReadOnly()
        {
            return false;
        }

        [ConfigurationProperty("Epic", IsRequired = true, DefaultValue = "")]
        public string Epic
        {
            get { return (string)this["Epic"]; }
            set { this["Epic"] = value; }
        }

        [ConfigurationProperty("Colour", IsRequired = true, DefaultValue = "No description.")]
        public string Colour
        {
            get { return (string)this["Colour"]; }
            set { this["Colour"] = value; }
        }

        public Color GetColour()
        {
            return Color.FromName(this.Colour);
        }
    }

The PropertyGrid is actually bound to the WatchConfiguration class.

Any help would be greatly appreciated!!!