I would say before:
"On the other hand, you are right, I had MADE a redundancy in my userChrome.css, so I made a correction after your reply."
Sorry, my English is not too good.
I hope you could understand the essence of my message, even so.
Regards,
E.W.
P.S.
The problem persists, so I would be thankful if you or someone other expert can share with me some tips & tricks to fix it.