https://www.zkoss.org/wiki/Small_Talks/2017/October/New_Features_of_ZK_8.5.0#Provide_Source_Maps_for_WPD_Files
correct debug setting. separate zk configuration on development environemnt and product environment https://www.zkoss.org/wiki/ZK_Configuration_Reference/zk.xml/The_Library_Properties/org.zkoss.zk.config.path