I have started using a shared calendar on RadDatePicker.  I also added a JavaScript example found I believe in the Telerik forum to set the min date of one RadDatePicker to the chosen date on the other RadDatePicker for a date range.  This isn't working correctly with a shared calendar because setting the min date on one RadDatePicker sets it on the calendar for both RadDatePickers. My solution was an OnPopupOpening function on the RadDatePicker to reapply the min/max dates to the calendar.  Here is the code:

    function onPopupOpening(sender, args) {
        var box = sender.get_dateInput();
        var cal = sender.get_calendar();
        var min = box.get_minDate();
        var max = box.get_maxDate();
        var mindate = [min.getFullYear(), min.getMonth() + 1, min.getDate()];
        var maxdate = [max.getFullYear(), max.getMonth() + 1, max.getDate()];
        cal.set_rangeMinDate(mindate);
        cal.set_rangeMaxDate(maxdate);
    }

My suggestion is to either have this done automatically by RadDatePicker or include something similar in the documentation for others who may have the same issue.

Regards,

Greg