I have a question.when I open my website in ie8,Month control can not load and a error like(Done,but error on this page) in the status bar.So that I check my source code and find out ,when I set CssOnly=true .this error is happen.
This looks like a bug, indeed. It will be fixed shortly.
Thanks for reporting the problem.
This bug should be fixed now in build 7.4.2951 (see the sandbox at http://www.daypilot.org/sandbox/). Please let me know if there is any problem.