Wanted to post an answer to my question just above that I discovered.
In the EQUI_Animations file of your chosen UI, search for "A_SpellGems"
This will lead to a grid section which was alluded to in the OP but not called out.
In newer UIs the CellHeight and CellWidth are set to 28/36 respectively. Most of the spell gems provided in the OP are designed for a 24/24 sizing, so updating those 2 attributes will fix the issue of black box spell gems
|