Ever wanted to sort the Items in your creative tab in a specific order? I'm going to show you how.
You are going to need a new class that extends CreativeTabs. In that class you override the displayAllRelevantItems method. It is the core method of the tab, it fills the NonNullList<ItemStack> parameter with the ItemStack instances that should be displayed on this particular tab. The idea is that you first call the super method to fill the list and then sort it, u