Advancement screen shadow renders below item icons

Advancements window has an incorrect render approach of the layers of GUI, displaying the blocks and items slot icons too far in front of the rest components in the window - resulting in the main window texture to be behind the icons that should be in the window. Every other element of the window seems to be correct, only the slot icons are wrongly displayed.

Steps to Reproduce:

• Look closely at the default Advancements window, where you can see the problem.
  OR
• Edit resource pack so the retextured window is slightly wider for example to see the problem immediately.

Observed Results:
The shadow of the Advancements window (and so the whole texture of the window) is behind the item display render.

Expected Results:
The Advancements window is in front of the item display render and all the components that are inside of it.