I was trying to create a dripping effect inside of a cave (in creative mode). I wanted the drips to come out of a slab, but I had placed the water source too far up. I then placed another water source underneath the first one and quickly put a slab in the lower half of the second water source. The drips are fine, the problem is that the water texture is visible on the bottom of the slab. I tried replacing the slab and placing a block underneath it, but no matter what I try the texture doesn't seem to go away.