[typo] Sidebar not working under Typo 2.5.6?

[Julian Yap]

Hi,
I just installed Typo 2.5.6 under Ruby 1.8.2.  Not sure what
version of Rails I'm running (or how to find out).

I can't seem to be able to add items to the Sidebar under Typo
Administration.  I can drag the available items and drop them
anywhere on the browser screen, including dropping it to the
"Active sidebar items" box.

When I drop it in that box, it doesn't look like it does
anything.  When I click on Publish Changes, nothing changes.

I can however remove an active sidebar item fine.

I've tested this under Mozilla Firefox 1.0.7, Mozilla 1.7.6 and
IE 6 and it does the same thing for all.

Any clues?

Regards,
Julian