In previous versions (going back a couple years), it was possible to make Thunderbird display the calendar on opening, by specifying the -calendar command line parameter. I know it is possible to open Thunderbird to something other than the Messages tab because when I twiddle add-ons and restart TBird, it displays the Add-ons tab on startup! Can we restore the ability to start in calendar view on startup? Maybe the Lightning team can provide an option to startup with the calendar tab, the same way the Add-on tab manages to assert itself on startup? This would be very helpful for accessibility and day-plan automation.