I'm also affected by this problem, I use a client/server thin client program that's normally minimised to the system tray, works fine on previously version of kubuntu but on 15.04 I get no system tray icon so I can't access the client program to use it at all.
I'm also affected by this problem, I use a client/server thin client program that's normally minimised to the system tray, works fine on previously version of kubuntu but on 15.04 I get no system tray icon so I can't access the client program to use it at all.