Simple Date Picker Not Working

-- HikaShop version -- : 2,5,0
-- Joomla version -- : 3.4.3
-- PHP version -- : 5.4.3
-- Browser(s) name and version -- : All
-- Error-message(debug-mod must be tuned on) -- : Uncaught TypeError:
Cannot read property 'length' of nullDate.print @ calendar.js:1
Calendar.callHandler @ calendar.js:1
Calendar.cellClick @ calendar.js:1
Calendar.tableMouseUp @ calendar.js:1

Replicate Error
1. Create new custom field for order table, using simple date picker
2. Save and publish to frontend
3. Frontend date picker on checkout page have no function with above error in console
4. Backend date picker in editing custom field have no function with above error in console

Updated to J3.5.1 Hikashop 2..6.3 and change in Display -> Custom fields Simple to Advanced data picker.
But it don't support cyrillic chars? Strange symbols instead text.

Hi
Date support in joomla is really a MESS , i ask many questions and create many posts about date support and filter range and date format ....
Good luck