1. What you describe as a bug is currently working as intended.
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It shouldn't be all one block since the fact of the matter it has always been available as several blocks (separate faces of the mushroom block and stem were all separate blocks.) I have been in Minecraft pretty much since the beginning and should know my way around it.....
2. The server described in the video is using Bukkit, which is a server mod that makes it possible to place those blocks.
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Yes indeed Bukkit is a server mod that replace hey0's modification and mushroom blocks don't have a separate plugin to address their rotational faces as seeing it was a base part of vanilla Minecraft coding.
3. This is how it worked since the introduction of the Silk Touch enchantment.
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When the Silk Touch enchantment was first introduced it allowed for these blocks to be collected but at the area in which they were facing and in fact were not all the same block and I know this because of the fact I had tested before building in a survival single player session (Offline/vanilla/un-modded client since back then I was not to keen on mods for Minecraft.) Upon getting a silk touch pick I had cut down the giant mushrooms and indeed got separate blocks from this to build a roof for my house.
Okay thanks for the spam deny [Mod] Tails obviously you are not doing your job right because this is an issue 😛
-Firstly I know in my screenshots I had a modded client (since I use optifine/shaders/rei's minimap) but I also tested this on a non modded client as well and the same bug happened.
-Secondly to validate my point I have a video by crafted bonus talking about there mushroom biome build and at 4:30-5:00 minute mark should be a presentable area for the describing of the bug. (http://www.youtube.com/watch?v=s9ALSxoF0Hc&list=UUnidU2BkALEtVdrNUOdnlvA&index=19)
-Thirdly there is no plugin for this type of thing since it was a feature in Minecraft and had been there since giant mushrooms, mooshrooms, and mushroom biomes were created.
So I was able log into via minecraft.net like the usual email and password
Never sadly had the ability to migrate. As though when I log in via the launcher it says play demo version, but I had bought a prepaid card years ago. But if I have to buy a new one I can.