What you can do is remove the panel completely.
Then you add a new empty panel and start filling it with all the items you want to see in your panel.
This should do the trick.
No more Windows and Gates since Ubuntu 8.04, used 9.04, 10.04, then switched to Kubuntu because of Unity and Gnome 3.
After that it is Mint, used 9 till 17 all in KDE version and loving it.