How do I switch inventory slots?

hey, I have a (barely) working inventory system, I can switch between empty slots and it works perfect but when I pick up weapons anything past the first slot but it works once I go back to the first one, does anyone know why?

I would say a few things here, get in to the habit of using the trigger events (with the green arrow) at the topmost level of the event or things get really weird. In your system condition slotUse=itembox.slotnum, you are not really picking an item box, you should use the itembox object as the condition and say where slotnum = slotUse, this then picks an itembox you can use together with the weapon condition.