void setLocation(ProgramLocation location) {
		if (isFiringNavigationEvent) {
			return;
		}

		if (!followLocationChanges()) {
			return;
		}

		if (!isVisible()) {
			return;
		}

		if (location == null) {
			return;
		}

		Address address = location.getAddress();
		FunctionManager functionManager = currentProgram.getFunctionManager();
		Function function = functionManager.getFunctionContaining(address);
		if (function == null) {
			function = plugin.getReferencedFunction(address);
		}

		doSetFunction(function);
	}
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