That means it is Roku tv remote, which uses different IR commands then roku streamer like the express. What is the model number of the remote, its in the battery compartment? Is there a pairing button there?
I hoping if there was pairing button, it could have been paired to the 3900, but witout one its just useless to you roku tv remote. Just make sure the next remote doesn't have tv controls, which are only roku tv use. Like the last remote priced at $14.99 on this page: