I don't know if that is the case, Matt, but I'll check it out. Might have picked the wrong shortcut to open the file. Thanks.
I might have this wrong, but in order to get the (non RayTraced) background in all detail through a glass sheet, you need to up Render Subdivision settings to 1, even if there's no reflection and refraction is 1. Am I correct? And would it be interesting to have it so that you needn't alter subdiv if using these glass settings? Not a lot of users will know how to.
I did a small experiment, but then the render took twice as long (crop, so it may probably be negligible on a completer render if the sheet isn't very big). So I added a default shader for opacity of the most part of that sheet, and that works pretty good, if the cloud isn't too dark.