[incr Tk] is a framework for building mega-widgets using the
[incr Tcl] object system. Mega-widgets are high-level widgets like
a file browser or a tab notebook that act like ordinary Tk widgets
but are constructed using Tk widgets as component parts, without
having to write C code. In effect, a mega-widget looks and acts
exactly like a Tk widget, but is considerably easier to implement.
from nikns at secure.lv