void programActivated(Program program) {
		if (!followLocationChanges() && currentProgram != null) {
			return; // don't respond; just keep our data
		}

		currentProgram = program;
		currentProgram.addListener(domainObjectListener);
		setLocation(plugin.getCurrentLocation());
	}
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