There is one feature whose implementation got dragged out for quite a while now, and gets requested with each new release of the KDE Workspace - being able to tell an application always to be shown on all activities, or on a specific one.

The reason for this taking so long is that KWin <-> Activities relationship started in the era when I did the activity manager related things (aka /the under the hood stuff/) while Chani connected them to Plassma and KWin. She is not working on KDE anymore, so these areas got a bit forgotten.

Now, the feature will be finally available in KDE SC 4.9.