private void updateTitle(ProgramLocation location) {
		if (!isVisible()) {
			return;
		}

		Function function = getFunction(location);
		if (function == null) {
			setSubTitle("NOT A FUNCTION");
		}
		else {
			setSubTitle("");
		}
	}
Invoked when a new location has been detected in the listing. When
this happens we need to update the tag list to show what tags are assigned
at the current location.

@param loc the address selected in the listing
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/function/tags/FunctionTagProvider.java