What I expected to happen was...:
That creates a water mist through glass.

What actually happened was...:
That you can look through glass as normal, even though you are in the water.

Steps to Reproduce:
1. Fly around in the creative mode on a dark prism blanket in the water. Then look straight through the glass, the glass is normally transparent, as if you were above water.
I am not quite sure that the water consists of 100% swelling blocks or running water.