I thought this should be a simple thing, but I simply couldn't figure out a way to define the name of the nodes in my dialogs, while constructing a Dialog.
Clicking in "Name this node..." doesn't cause any reaction from the browser. Clicking in "Untitled Node" makes that region of the screen (where "Name this node..." is) blink, but I still can't edit it.
I guessed it might be a browser issue; but I tested it with Firefox 38.7.1, IE 11 and Chrome 55.0.2883.87, and all of them present the exact same behavior.
(Another possibility is that the reason is that I am using a 30-days trial version, but I couldn't find any answer for that anywhere)
As stated in the comments: The feature is active now. Dialog nodes can be named either in the UI or when editing the JSON file.