That part hasn't changed: before and now the countries list have always been just plain basic/standard drop-down lists (unlike the makes list which is something specific managed by the site).
As this is not something that the site handles, if there is a behavior change it may be due to an update of your browser.

One thing that can have an influence: now that the update history is displayed below all these fields, the page is longer, this can maybe in some cases modify the behavior?