Cannot select event types in planner

Cannot select event types in planner

Hi!
When I want to add an event in the planner, I can't seem to select an event type:
Whenever I try the drop-down, I only get a single square - I tried the portable version both on a desktop with AMD and a laptop with Intel processor. It is almost as if there is nothing linked to the drop-down control...
Please see the attached screenshots and advise if I am doing something wrong.