Side note from JIRA: "Version with id 'PE 2015.3.1' does not exist." so marked the latest version available to create the ticket.
Trivial enough it hardly seems worth bothering you guys with a ticket. But – it would be nice if in the Nodes > Classification > Classes section of the console where you have "Class definitions updated X minutes ago [o] Refresh" - if that little icon would animate to let you know the refresh is in progress after you click the button/link to make it happen.
Right now, the icon and text simply turn gray and are disabled until the refresh is complete. Again, it is a simple and little thing, but it would be a nice to have the visual indication that your request to refresh the class definitions is in progress.
If it matters, I'm currently viewing the console (2015.3.1) using Chrome "47.0.2526.111 m" on Windows 7.