Yeah, that was my folly - I've not used FS2 since the implementation of "mod folders" in the launcher so it didn't occur to me that the newly installed shadow stuff was being overwritten by the other mods in the folder I had selected.
A bit of constructive criticism for everyone here - as an outsider - it really can be confusing when installing mods for games for the first time. Some games are lucky and just have one launcher that you can select mods from using a check box or whatever... and it's clear that folks here have tried to make it easy. But for those of us who haven't followed progress it can still be confusing!
No slant against anyone in particular here. But making the great new features that FSO etc. possess available to the "newbie" is crucial and it's something that hasn't always been easy to follow (the FSO Installer was a complete joy to use as it does it all for you - but even that doesn't provide detailed data of how much file space each mod might use which makes it difficult to know how long is left to install everything or whether you'll run out of drive space in the process.)
Please don't consider this a rant though, more... food for thought when releasing new features. I know this one (the shadows function) is in alpha so no great expectations of support there but in general it can really help those of us with less tech savvy or experience from making silly mistakes like I did