In some versions of Altium, the mouse input doesn't work in the dropdown. If this happens, use your keyboard to change the dropdown value instead. To see how, please refer to this video below.
Why can't I change the mechanical layers in the Current Layer Mapping window in Altium?
In some versions of Altium, the mouse input doesn't work in the dropdown. If this happens, use your keyboard to change the dropdown value instead. To see how, please refer to this video below.