I'm putting this out here in case anyone else has the same issue I had. It was temporary so it kind of fixed itself, but it took a bit of manipulation to do it I think.
I copied a full page from a backup copy of a project (direct previous backup so everything was pretty much the same, but I wanted one of the pages that wasn't in this project to be added to it. So ...
I did the right click, copy to ... chose the other project that I had open as it was the only one that showed up. The page was added to the new project, YAAAYYY! TY for that! But ... when I went to open it, it was like the app was stuck, but not totally, only for that page, it wouldn't allow me to open it. No right click menu, nothing, as if it didn't exist. I deleted it, recopied it and then it allowed me to open it YAAAAYYY ... but ... lol When I check the Preview in browser, it couldn't display it, said it wasn't available or something (I should have written the error down, but I didn't, sorry.
So I deleted the page from the old backup and POOF! It then worked perfectly! Of course, we don't want to have to delete things from other projects to do this right? So ....
I hit undo to put the page back in, and everything still worked perfectly! YAAAAAY!
But of course, this shouldn't happen at all so, if it happens again I will let you know, but putting this here as a record so I don't forget and of course in case anyone else has these issues to report as well.
Thanks again for adding this copy feature! This will save soooooo much time!