public virtual void RemoveColorWithKey(NSString key)
{
NSNotification n = null;
if (_is_editable == false)
throw new Exception(@"Color list cannot be edited");
_colorDictionary.RemoveObjectForKey(key);
_orderedColorKeys.RemoveObject(key);
// We don't support notifs for now ...
//n = NSNotification.NotificationWithName(@"NSColorListDidChangeNotification", this, null);
//NSNotificationQueue.DefaultQueue.EnqueueNotification(n, NSPostASAP, NSNotificationCoalescingOnSender, null);
}