Help: meaning of the panelize command in left/right menus

[cri at linux.it]

Hi, I can't find any information in the internal help, or man page, or wiki,
about the "Panelize" command in the "Left" or "Right" menu.

I suspect it is related to the (well documented) "External panelize" command,
but when I select it, I'm left clueless with an empty panel.
Now what?

Cri