Must Logout from Admin Account for Nice Menus to Work

[ Ubuntu; Drupal 7.15; Zen 7.x-5.x ]

I posted a similar note on 'support@drupal.org', but didn't get my
"issue" resolved. So, I am now sending it here ... this after
doing the usual "online check" for a solution ...

I am having problems with Nice Menus (placed in Zen's Navigation region).

In particular, (1) the three top-level menu items are in two rows as
shown here:

http://cs.appstate.edu/~khj/nice-menu-probs.png

Also, (2) the sub-menus aren't appearing when I hover or mouse down on
the items with an "expansion arrow". The "arrows" suggest that, in
fact, the sub-menus are in some sense recognized ...

An *important* comment: the Nice Menus work as expected if I
logout of my admin account! Once I login, the menu items are again
on two lines, etc. Weird!

Note that I have another site working fine with Nice Menus using the
7.x-3.x version of Zen (both logged in and logged out). I've tried my best to
compare the two sites to detect any different configurations &etc ,
but all I have been able to find are the two different versions of Zen.

I know I'm leaving out a lot of detail. Am more than willing to
describe more if needed.

Thanks for your help!
--
Prof Kenneth H Jacker khj@cs.appstate.edu
Computer Science Dept www.cs.appstate.edu/~khj
Appalachian State Univ
Boone, NC 28608 USA