From Minecraft Wiki
October 4, 2012
12w40a is the tenth snapshot released for 1.4.2.
- Added Swamp Hut structures, for Witches to spawn in.
- Added superflat preset "Redstone Ready" with 52 layers of sandstone, 3 layers of stone, and 1 layer of bedrock.
- Custom Item naming NBT tags (intended for custom map makers).
- Using the NBT, it is possible to add custom names to items, as well as a lore list for that item.
- Flatworld configuration now allows you to generate trees, strongholds etc.
- Now pumpkins, tall grass, flowers, trees, mineshafts, dungeons, strongholds, lakes, desert wells, ravines and ores will spawn on superflat maps
- Better inventory management
- The pick block action now works on blocks that are represented as items in the inventory. (E.g.: Repeaters, redstone dust, tripwire)
- Pressing the 1-9 hotkeys while hovering over an item will put that item into the inventory bar.
- In creative mode, you can now shift-click items from the hotbar to the survival inventory screen
- The left-click action will no longer open doors, pull levers, push buttons or open trapdoors. Use the right mouse button!
- Firespread has been slightly nerfed again to prevent infinitely spreading fires
- Beacon Texture altered, as well as the beam.
- Eye of Ender can now be used in superflat worlds. (only if stronghold generation is enabled)
- Slimes now spawn in Swamp biomes at low light level.
13 bugs fixed
- Fixed the wither's starting explosion not being disabled by the mobGriefing gamerule
- Fixed a few crash bugs related to world generation, map item expansion, and other things.
- Reverted previous lighting changes, which corrected such bugs as:
- The Nether being extremely CPU intensive.
- Map generation taking extremely long.
- Fixed mob AI considering cobblestone walls as blocks of normal height.
- Fixed a few texture oddities with the witch.
- Fixed entities in water producing glitchy water sound.
- Gaining multiple levels at a time will no longer play the leveling up sound over itself as many times as leveled.
- Fixed the "A 64 bit Java installation is recommended for 'Far' render distance (you have 32 bit)" message being covered by the bottom 2 buttons.
- Fixed pets teleporting around randomly
- Fixed being unable to place paintings larger than 1x2 and them popping off if they have been placed before
- Fixed destroying blocks under you with Efficiency-enchanted gear
- Fixed potion spawners crashing the game