Sidebar patch: 1 keybinding not working

[RLB <redlob+mutt-users@xxxxxxxxx>]

Hi group,

I applied the sidebar patch to my Mutt 1.5.12. It works great, except
for one thing: sidebar-open doesn't work. Sidebar-next and sidebar-prev
work OK though. If I press CTRL-O, no mailbox gets opened.

What could be the problem here ?

Thanks,
Dick