I plan to use the groupTemplate functionality of dropdownlist. There is a weird behaviour that also appears in your demo: groupTemplate -> Preview
I also have attached the visual bug as screenshot:
1. The very first group (Argentina) does not consider the groupTemplate as all other groups do.
2. The very first group (Argentina) gets his own line while all other group titles appears on the line of the first group entry.
I would expect the same behaviour for ALL group names. Is this a bug and if not, how can I fix it to make it look/position all the same?