Tabble is a small alternative X shell which presents your programs in tabs for easy launch. Tabble is not meant to replace a window manager, just complement it. Light window managers benefit the most from tabble.
The idea is that tabble is 'always on top' so multiple launches can be made without re-navigating a menu hierarchy or clearing the desktop.
The above window, customized to your choices, can appear at a fixed position on your screen so you can spawn a few things quickly. Hit the hide button and it's out of your way, and the next switch to tabble will be faster.
One of the reasons for tabble is that it can be started from within a chroot (32 bit inside 64 say). Other programs within the chroot can be easily spawned from this tabble.
KDE/GNOME could use this concept but there is still a case for a standalone program for those who switch between window managers - because only one configuration file needs maintaining and it can be shared.