private void installHelpLocation() {
		LocationReferencesService locationReferencesService =
			tool.getService(LocationReferencesService.class);
		if (locationReferencesService == null) {
			// not installed yet; listen for the service to be installed
			tool.addServiceListener(helpLocationServiceListener);
			return;
		}

		// this action is really just a pass through for the service
		setHelpLocation(locationReferencesService.getHelpLocation());
	}
We need this when our plugin is loaded before the service we are using
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/symboltree/actions/ShowSymbolReferencesAction.java