Can not change order status in Orders listing

-- HikaShop version -- : 2.6.2
-- Joomla version -- : 3.5.1
-- PHP version -- : 5.6
-- Browser(s) name and version -- : Firefox 45.0.2 and Chrome 49.0.2623.112
-- Error-message(debug-mod must be tuned on) -- : none

May be since last update, or may be since using SSL, it is not possible to change my order status in the Orders listing in the backend of two sites with Hikashop now.
So in the list, in the table under the header 'Order status' I try to change the status of an order. Normally a popup asked me to confirm. But now nothing is happening, just nothing.

In two browsers on two sites I have tried, also configured them without blocking popups.
Any idea?

TIA

Thank you. No more Mootools. Problem solved.