Just wondering how things are going?

Some dogs are alot more protective when onlead, as the fear of not being able to escape gets to them. Growling/ Scolding will not help agression in anyway. You are better off to divert the dogs attention onto somthing else. Eg if you are standing around and Rio lunges, do a quick turn on the spot and try and get the attention back onto you.

If Rio has not been spayed yet then she could be coming into season and is not liking the attention/ sniffing from other dogs. Just a thought.