private void initialize() {
		dragDropManager = new DnDMoveManager(this);

		setRowHeight(18);

		nodeList = new ArrayList<>();
		viewList = new ArrayList<>();

		if (treeModel != null) {
			treeModel.addTreeModelListener(new ProgramTreeModelListener(this));
		}
		setEditable(false);

		nameIndexer = new StringKeyIndexer();
	}
Initialize data structures, popups, and create listeners.
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/programtree/ProgramDnDTree.java