1. A method comprising: instantiating, in a computer system, a first user interface (UI) session in communication with a corresponding first UI agent instantiated in a first client computing device through a first UI connection, wherein the first UI session handles transactions for information from a data source for the first UI agent to display a first UI comprising the information from the data source on the client computing device; associating, in the computer system, the first UI connection with an application messaging channel (AMC), the AMC comprising an interface for communicating between the first UI session and a plurality of other UI sessions instantiated in the computer system; receiving, in the computer system, on the AMC a notification of an event in the data source from one of the other UI sessions; and sending the notification of the event from the computer system to the first UI agent through the first UI connection.