Issue description:

Storage drawer connected to drawer controller. External storage. Items in all types of drawers are visible in RS system and manipulating items in un-upgraded drawers works normally.
Manipulating items in creative upgraded drawers causes java exception.

What happens:

NPE in java server thread
https://gist.github.com/jco2641/4da4516a1b1e391bcf1d1b4fb627165c

What you expected to happen:

Able to manipulate items in upgraded drawers

Steps to reproduce:

1. Click item in RS grid that is stored in upgraded storage drawer
2. Operation fails

Version (make sure you are on the latest version before reporting):

• Minecraft: 1.12.2
• Forge: 14.23.3.2678
• Refined Storage: 1.5.33

Does this issue occur on a server? [yes/no] only tested single player

If a (crash)log is relevant for this issue, link it here:

https://gist.github.com/jco2641/4da4516a1b1e391bcf1d1b4fb627165c

Fixed for 1.6

After a lot of trial and error, I found this issue with connecting RS to Creative upgraded item storage.

Any progress on 1.6 release?