item/parent_type=/obj //Not real code. Just what you need to know.
container
parent_type=/item
var
capacity
New()
..()
src.suffix="\[[capacity]\]"
Entered(item/I)
if(!istype(I)) return
if(src.capacity--)
src.suffix="\[[capacity]\]"
..()
Entered(item/I)
if(!istype(I)) return
src.capacity++
src.suffix="\[[capacity]\]"
..()
Problem description:
Things move okay, but the capacity does not increase or decrease.