JJ,

The classic and new mode is only for the Start Menu. The taskbar
doesn't have this mode.

You're confusing me there. The taskbar certainly does have a classic mode.
But I agree with you that particular change only gouverns the start menu
(alas...).

And that 0x20 is the offset to the data, not the value of the data.

Its both. And yes, I also marveled at the coincidence of it. :-)

Can you tell me when this setting is used (by the OS I mean) ?
....
It's used when a namespace doesn't have any default file view yet.

Ah. Thats why some tweaks remove all those other "bags" entries from the
registry. Worth a try.

It might be wise to forcefully close the desktop process before
applying your settings

??? I though that doing that would automatically reboot the 'puter ...
(which means that applying changes after doing that would not be a ...
problematic thing to do (reboot during applying changes and all that) ).

Regards,
Rudy Wieser

P.s.
I've mentioned that I would probably try to have AutoIt have a go at it.
Alas, its wrought with its own problems. :-( :-)