A little obscure fact about WebPart Connections.
If you are writing a WebPart that is a Provider as well as a Consumer it is better to give your ConnectionPoint's unique Ids.
Infact if you have multple Providers on the same WebPartPage the connections wont work unless each ConnectionPoint like so
[ConnectionProvider("DisplayName", "ConnectionPointId")]
public IWebPartField ConnectionInterface()
{
return this;
}