@Override
			public void actionPerformed(ActionContext context) {
				FunctionSignatureFieldLocation location = new FunctionSignatureFieldLocation(
					currentProgram, currentFunction.getEntryPoint());
				goTo(location);
			}
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