I have been worked with zk in a chat project. I used zk version 3.0.4 but I had problem with Desktop, sometimes it didn't activate, I sent messages and everybody received but I didn't receive it. I thought to update zk version 3.6.1 to resolve this problem. The chat worked correctly on Firefox, but on IE 8 showed the message: "Server failed to process your request. Try again? 467: Incomplete request", and my message wasn't sent. This problem happened with buttons, menubar and toolbarbutton. I tested in others tools that we developed, but all had the same problem. I tested with zk version 3.5.2, 3.0.8 and 3.0.5 too but this problem continued. The tool worked correctly only with zk version 3.0.4 on IE. But all versions worked on FireFox.