1. Added an HTML element, and added the body code for the Lightbox.
2. Added the correct folder to the resources.
3. Added the Head code for the Lightbox into the Footer (per another recent thread)
The end result: Lightbox was malfunctioning, the same as when I use to put the Head code in the Head area. When I previewed in a browser and clicked on a photo, the photo pops up, but it does NOT have the nice white frame and navigation controls, and it does not go the next photo. NOT working as it should.
I checked, double checked, and triple checked my code entry in all 3 places. I even uninstalled the program and re-installed it. Couldn't get it to work. I even checked the code on my previous successful Lightbox that I had done in RSD. The code was identical. I was getting a little stressed.

Finally, I tried something a little unorthodox. I went to where the footer code is entered, and clicked on 'Add Resource'. Then I clicked on the components THAT WERE ALREADY THERE (I know that doesn't make sense, but stay with me) and clicked 'Select'. The dialogue box would close, as it should. I kept on doing this until every individual component (that was already there) was selected.
Here's the weird part. As soon as I finished doing that, the Lightbox starting working perfectly!
I was doing all of this in a test RSD file when I got it to work. So then I opened the website I was working on in RSD, and did those same steps again, and it made it so the Lightbox worked in that RSD file as well. So I was able to repeat it.
Some kind of goofy little bug I guess. For some reason RSD is not recognizing the all of the elements inside the Lightbox resource folder when added in the normal way. The funny thing is, I haven't had any trouble with any of the other resources doing this goofiness in the rest of my project. Only the Lightbox resources files so far. I could be wrong, but it seems like this little bug is connected somehow with the putting of the Head code into the footer area?
In any case, I hope it is something that can be tracked down and fixed. It is a lot of extra work to have to go in and do all of that each time I add a Lightbox. The funny thing is that I had no trouble with the first couple of Lightboxes I added. A head scratcher for sure.