Left Side mini-month/calendar list missing

[riweber]

I have Lightning added to my Thunderbird. The calendar pane is visible on the right side, and my reminders work, but I used to have the month at the top, and it hasn't been there since one of my updates. I don't recall which. I've gone to View, but Calendar is greyed out. I've tried checking the settings from Lightning, itself, but there's no setting to bring up the monthly grid. HELP!