How to show attribute dropdown in add to cart form in Commerce 2.x The attribute dropdown list doesn't show, instead I get an autocomplete field labelled "Product Variation" and it contains the full title of the variation. When I enter text, a list of variations appear but when selecting a different variation the product doesn't refresh. 

I would like it to show the label of the attribute with a dropdown list of the values. I'd like it to say "colour : "Value"". I have two attributes one showing a weight capacity the other a colour. They are both appended to the variation title but I need to select combinations of the two. I've trawled the internet and it seams the dropdown list should work out of the box. 

I have a matching Product type and variation type. On the manage display of the product type the variation field format is "Add to Cart". On the variation type the attribute field is enabled but it doesn't show up.

Where am I going wrong please?
You have somehow disabled the proper widget. Go to the "Order item types" page and click "Manage form display" for your order item type, the widget for the "Purchased entity" field should be "Product variation attributes".

I would love to find out how your system ended up in this state. Was this a fresh install? Did you create a custom order item type? Let us know in the Commerce issue queue.