Hello..have found my problem, case solved thanks
Be sure that if you create a new Calender you see three options to get he Calender infos...one Option is "Calender date filled in by URL"...all ok so far, so you can fill in a URL iCard or other link
But: if you create the calender without and save the new one without select an option, this Option are not more visible if you will change the new created Calender by edit
Seems this is wrong
Regards