Ditto...

Duplicate of T123762

this is not affecting only triggers.
It looks like combo boxes are broken for a specific position, for example Firewill's F-16 mod loadout module has same issue for Hardpoint 2. It is not possible to open that combo box to load a weapon

It's probably also a duplicate of T122322 which was reported 3 months ago. :)

I have the same issue but if you move the window a little and click on the arrow of the combo box it works. Try this and let me know

I found the same thing. If you scroll down to the bottom of thr trigger menu a bit, it will let you choose.