void programClosed(Program program) {
		if (program != currentProgram) {
			return; // not my program
		}

		program.removeListener(domainObjectListener);
		clearState();

		currentProgram = null;
	}
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