Fairly simple, in the default .6 build downloaded as an installer (I'm still trying to get build correctly before I look at source -- downloads slow on this con so don't have all of mozilla yet)
This is dealing with a profile (ealar) made from being default (haven't tested other scenarios yet) and switching to him, then switching back and forth (w/o reloading everything manually yet, since thats a real pain to do on this machine). Problem was persistant, whenever I 'loaded' a profile it would not display correctly.
:click -> Edit
:click -> Manage Profiles
:click -> (diffrent profile than current)
:click -> OK
:click -> YES (to reinit everything)
windows reinit's and stuff)
all Menu Icons are poof!)
I have not found a workaround yet (I'm prety sure a manual reload will fix it).