Its very hard to use the "Add files..." dialog to add a directory. E.g. if
you have a directory called "foo" with files in it and you want the
directory foo and all its contents in the archive like this:

foo/file1
foo/file2
etc.

If you go into the directory and press OK you typically just select the
contents and get:
file1
file2
etc.

If you go into the directory above foo, select "foo", and press OK it just
adds "*" in that directory instead. Even typing "foo" instead of "*"
doesn't help.

I've gotten several reports about this in the redhat bugzilla, for example:
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=77971