@Override
			public void actionPerformed(ActionContext context) {
				Object contextObject = context.getContextObject();
				GTree gTree = (GTree) contextObject;
				TreePath path = gTree.getSelectionPath();
				CallNode node = (CallNode) path.getLastPathComponent();
				goTo(new ProgramLocation(currentProgram, node.getSourceAddress()));
			}
A variable used to restrict open-ended operations, like expanding all nodes or filtering.
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/calltree/CallTreeProvider.java