A correction to my last post: when I went to edit the menu to add
--update-only to the yumex command line, I saw this:
/usr/bin/yumex -X install %F
This means that, as installed, yumex is expecting to be given a program
to install on the command line. No wonder it doesn't work! Removing
that fixed it.
Now, the question is, is this worth a bug report? I'd think so because
most users either won't know how to edit the menu or wouldn't be willing
to change it once they see what's there. Opinions?