There is a problem with combobox client error validation message in IE11.

http://zkfiddle.org/sample/21927bv/11-combos-error-message-problem

Avi file to see how to reproduce the problem(Sorry for the poor quality) is attached:

Select second combo(Child) which has constraint no empty but don't select anything from it, then select first combo and try to close the validation message that is displayed for "Child" combobox. The validation message doesn't close and everything is blocked. No error or warning message in console. In Firefox and Chrome everything is OK.