@Override
	public List<DataType> getDataTypesByPath(DataTypePath path) {
		List<DataType> results = new ArrayList<>();
		DataTypeManager[] managers = getDataTypeManagers();
		for (DataTypeManager manager : managers) {
			DataType dt = manager.getDataType(path);
			if (dt == null) {
				continue;
			}

			if (manager instanceof ProgramDataTypeManager) {
				// we put the program's data type at the front of the list so clients can tell if 
				// the types we have found already exist in the program
				results.add(0, dt);
			}
			else {
				results.add(dt);
			}
		}
		return results;
	}
Create the actions for the menu on the tool.
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/datamgr/DataTypeManagerPlugin.java