When a Bauble is equipped, is it possible to make it so that the background image of that slot is not shown? This means that I can use any texture for a Bauble without having the slot icon showing in the background. I'm sure this will be useful for others using the API, as well as resource pack creators.

The icon is actually part of the texture itself.

Not showing the default background icon when an item is in the slot is the default behavior in vanilla equipment slots too, afaik.

When thinking about it it seems quite simple:

Check for Item != null
- > Draw a piece of the gui under the item

You know, I never even noticed that the vanilla armor slots do that.

Sure, this sounds like a simple enough request.