I am surprised by your immediate response!
Frankly, I am an absolute beginer learning Joomla on localhost only, so far. It seems it is maybe a problem WinXP specific - in Vista it is OK (FireFox3.0)
Back to my default comp

:
FireFox error console message:
===================================
1] immediately after click on link in administration (opening a popup window with menus list):
JGears.I("module-status") is null
joomlaGears.js - line 132
2] after a click on "Add to Menu" link in popup:
window.parent.addtomenu_setMessage is not a function
line 36 in www page
followed once more with a message:
JGears.I("module-status") is null
joomlaGears.js - line 132
Sorry, no more info for now...
Thanks for your time.