study_key invisible when putting in to a chest?

[Russ Money]

Aww, why!
Okay, i have an big problem...

Everytime i trying to add a normal study_key or other item in to a chest or sometime's other entities like chest...

It's just invisible in-game and i can pickup it! So
I don't know what the h*** is that... But i need really help.

Most likely the key isn't invisible but kinda of sinking through the box. It happened to me with a note in a chest. I could think of a work around, but there might be an easier way to fix it.