Attribute Drop Down Menu Blocked In Front

[ebri]

Hi, I'm starting with prestashop and I have Granada template. I have created products and attributes and do the combinations.

The attributes are displayed in the front as a drop-down list, but when the user is displaying the list, to select the attribute value, he must keep clicking and select from the list while is clicking. If you just do a simple click (click and loose) you can see the list but it only recharges the default filter. I mean, it does not allow you to select from the list unless you keep clicking. We can say it works like a button.

How I can do so that when the user clicks the list stays deployed and you can choose the attribute value that interests you?

I hope I explained and thanks in advance!