Hi Lazar,
If you want to achieve this globally for all products, first of all, make sure these options are unchecked.
Secondly, the size attribute needs to be of the default select types.
BTW, you can also control this product-wise from the Swatches Settings tab of the product edit section.
Let me know if you have further queries or the issue is resolved.
Thank You
Specific dropdown
Lazar Stanojevic
Hello, I would like to know if it’s possible to have attribute for size (s,m,l,xl) be drop-down and rest to be select field.