TrayIcon blocks the U++ applications (windows and widgets does not respond to any mouse or keyboard actions, application simply freezes) when used with the GTK backend.
So neither Eyecare nor any other app using TrayIcon works when compiled with the GTK backend. (As a side note, Eyecare has timer problems on other backends too).
Tested on Arch Linux (linux 3.12-8, KDE 4.12.1, GTK2 2.24.22)