[Greasemonkey] GM_registerMenuCommand - problem with repeating menu items

[Ori Avtalion]

Hi,

Using GM 0.6.4
In my script here:
http://userscripts.org/scripts/source/1476.user.js

I'm registering two menu commands.

1) Each time I visit a new page where the script is triggered, it adds 
the menu commands again. After browsing a few pages, the list can get 
very large.

2) When I disable the script by going to another website, the old menu 
commands are still there, and are operational - they're executing 
functions that are part of an inactive script.

How can I reset and repopulate the menu after a page change or when a 
script disables itself?

- Ori