In order to make possible navigation of large hierarchies, widget folds as many nodes as needed in order to fit chart into available screen space.
Widget shows full size cursor item and its immediate children and parents, so user can click them and navigate further around current cursor item.
Widget supports selected (checked marked) items collection, all of them stay in full size so user can see them all the time during navigation around hierarchy.
Page Fit Mode defines rule of fitting chart into available screen space. Set it to None if you want to disable it.