question: public CollectionDragControl ( Map < Node , List < Node > > groups , Function < Node , VisualItem > adapter , Function < VisualItem , VisualItem > aggAdapter ) { this . groups = Collections . unmodifiableMap ( groups ) ; this . aggAdapter = aggAdapter ; this . adapter = adapter ; dragged = false ; selectedItem = null ; }
target:  Creates a drag control with a copy of the provided Map. 