my first idea would be to disable compression done by ZK's servlets, which is enabled by default. you can disable it in your web.xml for the loader and update servlet:

documented here: https://www.zkoss.org/wiki/ZK%20Configuration%20Reference/web.xml/ZK%20Loader https://www.zkoss.org/wiki/ZK%20Configuration%20Reference/web.xml/ZK%20AU%20Engine

my first idea would be to disable compression done by ZK's servlets, which is enabled by default. (double compression usually doesn't work) you can disable it in your web.xml for the loader and update servlet:

documented here: https://www.zkoss.org/wiki/ZK%20Configuration%20Reference/web.xml/ZK%20Loader https://www.zkoss.org/wiki/ZK%20Configuration%20Reference/web.xml/ZK%20AU%20Engine