my first custom world open only tried to make more worlds and i'm getting the same problem.
used task manager to close it goes to launcher if you go back in to minecraft if click on the world your trying to make it goes back to trying to load
sorry after re looking this is happening due to "MC-48122 Out of body experience - Player floats above bed while sleeping" floating 2 spaces above bed and roof only 2 spaces above bed so i was sleeping in solid rock which caused an x-ray view
still on going in Minecraft 14w08a and also see through terrain
this is all so in Minecraft 14w08a
same here
same happened here but to cobble stone
i only places when standing on shore and you jump while trying to place and when it places its placed on one block down from waters surface
this is the same on mine fast graphic effected only
my newly placed stairs disappear completely i place stairs move away from area come back and they're gone.