I know that KDE and Unity have adopted appindicators for system tray functionality: https://unity.ubuntu.com/projects/appindicators/ https://unity.ubuntu.com/pr

I know that KDE and Unity have adopted appindicators for system tray functionality: https://unity.ubuntu.com/projects/appindicators/ https://unity.ubuntu.com/projects/appindicators/ I'm not sure what you want in the way of unified startbutton API. Even within KDE itself it has Lancelot, Kickoff, and Homerun, all providing a sliding scale of classical start menu to Unity / Gnome / Windows 8 style dash. That is one domain that has demonstrably not one ultimate answer, and I'm a big fan of the KDE attitude of making multiple choices available with the default being moderate (search by default, tabs for programs / recents / power / etc).