KWin: Window tabbing
by mata for KDE
This feature allows you to tab windows together, the options to change between windows in the same group can be done by tabs marked outside the window or embedded in the title bar, a menu in the window title bar, or a shortcut. This feature would eliminate the need to implement this feature for single applications which will save a lot of work others that want to add tabs to their applications and some other window managers already have this feature included like Fluxbox, Ion, wmii.