It seems like some incompatibility between thesorting and filtering.
No, not filtering with sorting but calendar issue.
Just click event bubbles because seems onclick="Event.stop(event);") is handled erroneous in 3.3.x.. I didn't checked by believe that it just doesn't executed correctly when click is in popup. If so need to do one of the things
- patch the component to make onclick work properly for all the component including popup.o
- create workaround with external sorting definition. If that case you will have full control on it. (E.g. will be able to check onsubmit for your sort support if the calendar was an original event source)
- bind your own handlers to calendar elements click using jQuery instead of built-in attributes.