MiiNiPaa

So it is intended to crash minecraft when forbidden item present instead of gracefully handle it?

Main point of isuue is crash, not the item not-dropping.

I believe it relates to the MC-30940.

I believe it is intended and was in one of Dinnerbone tweets

The truth is that naming a mob not only changes his name, but sets PersistenceRequired flag too.
You should add PersistenceRequired:1 to your summon command

TL;DR: Intended

Some servers run a mod which hides far away chests. It might be the case.

Because it is /toggledownfall without spaces

So are torches, snow and everything else. Was that way since enchantement table introduction and probably intended.

Workaround: Open your <minecrafetName>.dat in <YourWorld>/players (if multiplayer) or level.dat if singleplayer with some NBT editing program. Then find "y" (in player subtag for level.dat) variable and change it to reasonable value.

I believe that if, say, minecraft 5.100.1 will enter 5.100.2 server and one of the differences between versions is that anvils will repair 10% more durability, it will lead to desync.

Minecraft realms are currently availible only to chosen users.

I believe this is the part of uniform mounting system. Howeve to not be able to steer or SLOW DOWN is annoying as hell. I hope they will revert some controls to previous state

Cannot reproduce.
Note that bred horses can have up to 26 hearts (or even more)

I speculate that this happens because of suspended mobs accumulating fall distance (Like zombie pigman in lava lakes before)

I believe that now all entities you can ride on (Horses, pigs, boats and minecarts) requires use of sneak key to dismount it

Cannot reproduce. If you dont click on a fence instead of leash everything is working as it should.

EDIT: Reproduced it: Only top part of solitary (not attached to other fences/blocks) fence cannot be clicked on.

Crash reports contain info on internal gamestate which may be helpful.
They are required for all bugreports so if dev will need an error report, he will already have one.

Interesting... Not happens for me.

All items to be smelted should be loaded from the top. http://www.minecraftwiki.net/wiki/Hopper#Interactions

After passing through the water or ice sunlight statr to behave like every other light souce: decrease by 1 for each block passed (and additional 2 for water and ice). So two glass blocks and a layer of water give you sunlight level 9 right under lower glass block, 8 in next block and so on. Might be the case.
Edit: tested under your conditions: Daylight sensor works, but with decreased power you can expect from decreased light level.

This isn't a bug report.
Please ask questions on Minecraft Foruns: http://minecraftforum.net/
Minecraft Wiki have answers to your question:
http://www.minecraftwiki.net/wiki/Superflat
Look at the preset code example below. Also this http://www.minecraftwiki.net/wiki/Data_values can help you too

a) Pistons can be powered from two blocks above.
b) If said block changes, piston wont be updated.
This is (at least temporary) intended behavior
Like following:
place piston, place 20 blocks in front of it, power piston — not extending. Break any block from second to 12th — still not extending. Place any block besides piston — extending