I have the RuneScape 3 application on my system that has an icon attached to it, however the application launches a sub-process named "rs2client" according to System Monitor which doesn't have an icon - this results in an empty space on my Dash-To-Dock system tray.
The RuneScape 3 application icon shows briefly while preparing the actual client, in which the sub-process loads and the icon is gone (as the launcher application with the icon closes).
