Looking at this part but this suppose some changes on several myfaces converter and validators components that has the binding attribute or use the actual createConverter() from ComponentTag. ConvertNumberTag has it's own way to save and restore the state (doing the same of _DelegateConverter plus save some attributes), but ConvertDateTimeTag does not save its state(but has a binding attribute, so i think it's necessary to correct his impl as ConvertNumberTag does)
I'm wrong, ConvertNumber and ConvertDateTime that are created from ConvertNumberTag and ComponentDateTimeTag implements StateHolder, so there is no need to correct this impl. But I suppose this as a warning of side effects when coding the validator solution.
