Mabye this is not really a bug as such, I just noticed you cannont put things that were not originally equipment items in current item, such as hearts, and magic just to name two. Even though I made a item (item class hearts) into an equipment item I cannot really use it because I cannot put it on the subscreen, I know the easy fix is just to use a new item class (z###) and make it refill hearts since the hearts itemclass really does nothing anyway it is the counter ref and amount that refills hearts, the item drops are determined by ID number only so the itemclass does noting anyway. You don't have to rush to fix this and further delay 2.5 but I wanted to bring it in front of everyones eyes.
Can't put certian items in subscreen
Yep, a known limitation of the subscreen, and one of the Big Problems remaining pre-2.50.
I ran into this problem a while back when seeing if I could make a usable clock. I'm not sure if it makes sense to have usable rupees or hearts or magic containers (2/3 of those are just potion properties...) and I doubt any of the "instant use" items even have the right properties to be used as standard Link items. Still, the limitation remains in b660.
Solution: disable the Equipment checkbox for all affected item classes.
That's a hack, but not a solution, as it doesn't solve the problem of there being bug-prone duplication of the item class information in itemclass_str and subscreenitem().
What needs to be done is to fix the subscreen code to use the real item class list instead of its own copy, and to display the real item names instead of the hard-coded strings.
I'll do it in the near future.
Fixed in the next build, finally.