Thunderbird & Lightning

I know this has nothing whatever to do with Devonthink but I am getting more and more frustrated and wonder if the Devonthink community can help! I have recently switched to using Thunderbird with the Lightning add-on and I have managed to lose the mini-month and calendar list on the side of Lightning! I collapsed it by dragging the seperator bar and now can’t get it back—any idea how I can restore this view? I do have the mini-month and calendar checked in the View>calendar menu. Thanks for any help.

Problem solved! For anyone else who has this problem do this:
Close TB
Re-name the localstore.rdf file to, e.g. localstore.bak
Restart TB