Thanks for your reply. This is not really what I want. This code prevents input. Change amount is only possible with +/-. I have products which are not sold in quantities of f.i. 12 but only 1. If the customer needs 10 of this particular product he/she has to click 10 times on + (very unconveniant). In other themes it works perfect. If you have to order in units of 12 and customer types 13, a message apears that he has to choose 12 or 24. Xstore is not compatible with this extension of WC right now.