[Greasemonkey] Error: this.menuCommanders has no properties

[Andre]

with FF 1.5 and GM 0.6.4 I get the following error in the javascript 
console:

Error: this.menuCommanders has no properties
Source File: chrome://greasemonkey/content/browser.js
Line: 234

The source looks like this:

...
   // looping over commanders rather than using getCommander because we need
   // the index into commanders.splice.
   for (var i = 0; item = this.menuCommanders[i]; i++) {
     if (item.win == unsafeWin) {

...

Maybe this can be fixed?

Cheers, Andre