private CodeUnit getCodeUnitForCurrentProgram() {
		Address addr = currentLocation.getAddress();
		if (addr == null) {
			return null;
		}

		Listing listing = currentProgram.getListing();
		return listing.getCodeUnitContaining(addr);
	}
Subclass should override this method if it is interested in
program location events.
@param loc location could be null
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/processors/ShowInstructionInfoPlugin.java