Oh, a different Forum? Oops, sorry if I posted this in the wrong place. OK, I'll look for another forum, and I'll keep in mind a refresh button found bottom right. (Seems like the entire Library panel is blank, but I'll check.) Thanks.

You are right, ironsoul: There is a greyed out Refresh button in the bottom right corner. I clicked on it, and all the Runtimes appeared in the Library. Thank you very much.