Edit: in a "d'oh" moment I just realized that the wording on the slider is perhaps OK - it's just the function of it that doesn't apply greatly for shadows. I don't have the working files of that theme here as it wasn't made using my computer. I would have to engage my friend on that. 

I took this posting out of a different thread because I read that the issue here is probably not in line with that person's thread and issue.

 
If I might chime in.. I'm a relatively new user of Curtains(who do have a theme coming however)

I sat down with a friend and tried to help him set a shadow. He spotted it first and I concurred; a wording in the editor that might be be totally opposite of the function: If the slider is all the way to the right it would normally indicate 100% transparency - when reversing this(dialing towards the left even so not a total opposite) - my friend got his shadow.

Is there truth to this sighting? Turning it down to half would mean 50% opacity and 50% transparency. Should the wording be "Opacity" instead? All I know is what me experience was with making a shadow.

I'd like to think that I did everything to help making that shadow and my question surrounds this sighting.