Superflat customization menu shows item names instead of block names

The bug

Some blocks have special items to place them, which have separate names from the blocks themselves. Examples include “Wheat” (“Wheat Seeds”) and “Water” (“Water Bucket”). In the superflat customization screen, these items are used for the icon on the left. However, the item name is also used for the name of the layer instead of the block name.

This also causes MC-48058, where blocks with no items at all appear as “Air” with no icon, instead of showing the block’s name.

How to reproduce

1. Start creating a new superflat world (Singleplayer → Create New World → World → World Type: Superflat → Customize)

2. Go to Presets and paste in the following preset:

   carrots,potatoes,beetroots,wheat,melon_stem,pumpkin_stem,tripwire,water,lava,sweet_berry_bush,cocoa

3. Click Use Preset and look at the layers

Expected result

Next to the item icons, block names should appear: “Cocoa”, “Sweet Berry Bush”, “Lava”, “Water”, “Tripwire”, “Pumpkin Stem”, “Melon Stem”, “Wheat Crops”, “Beetroots”, “Potatoes”, “Carrots”

Observed result

Next to the item icons, item names appear: “Cocoa Beans”, “Sweet Berries”, “Lava Bucket”, “Water Bucket”, “String”, “Pumpkin Seeds”, “Melon Seeds”, “Wheat Seeds”, “Beetroot Seeds”, “Potato”, “Carrot”