I downloaded a theme package, then dragged it into Themes, getting the message that it installed correctly. However, when I tried to change to the theme, I got a message that it wouldn't look right because GTK+ wasn't installed.
OK, I thought, I'll install it..... so in Terminal, I typed
sudo yum install gtk+
but after a few lines of scrolling, I saw the message that GTK+ was already installed and updated.
Hmmmmm..... what do I do now?