This will more than likely be fixed in the next snapshot
Also you can use mods, like INVedit, to add enchantments to normal unenchantable blocks and items.
I think this is because every time you change what you are holding (including the quantity) whilst mining blocks, it resets the mining process. For example try mining something with your hand and then change to something else while you are mining the block. I am pretty sure this is not a bug and is intended, even if it is annoying
I don't really know what I wanted to happen, but it is annoying. Maybe if it did not allow you to get the lava bucket until you had a free space in your inventory.
The same thing has happened to me aswell. I went to the nether and when I came back, some cows were running around free from their enclosures.
This will more than likely be fixed in the next snapshot

Also you can use mods, like INVedit, to add enchantments to normal unenchantable blocks and items.
Is this in SMP or SSP?
I don't think that this is game breaking though...
Gamechap and Bertie have done a YouTube video of this.
I think this is because every time you change what you are holding (including the quantity) whilst mining blocks, it resets the mining process. For example try mining something with your hand and then change to something else while you are mining the block. I am pretty sure this is not a bug and is intended, even if it is annoying
I don't really know what I wanted to happen, but it is annoying. Maybe if it did not allow you to get the lava bucket until you had a free space in your inventory.
Ok thanks
I thought that this was intended? Like redstone and coal.
Oh right, Sorry I thought that you ment the item Nether Quartz, not the block Nether Quartz Ore. My bad.