Hi Simon,
Yes, not supposed to work but it does????
I think by overwriting the grey icons with the colour icons in the sytem resource file, the system will simple reference them as usuall.
I didn't find any metadata in the icon files so I guess that's why it would work after all, the icons are referenced locally.
My MBP was always a Lion machine so never had colour icons which I verifified afer my successful hack on my iMac (originally SL which had colour icons and the Lion OS grey icons after updatin OS) and opening the resource folder.
I just copied over the grey icons as stated and no worries.
Just one of those, it's just an image so how is it referenced/loaded/created to sit in the sidebar???
The grey icons for the mail sidebar are in there aswell but my hack hasn't worked there as yet.
Thanks for the reply Simon, it's good to spread the love.
Cheers Gaz