Comment 14 for bug 849624

(In reply to comment #9)
> I think that it would be cleaner to use a commandline switch instead of an url.
> The about: protocol is really handled somewhere else, and not in the power of
> lightning to change. The commandline switches are for consumers.

Well, I also tried this first, but there is a problem, when TB checks for new mails on start-up. TB does not recognize the '-calendar' switch and continues without attention to it.
This means, if no start page is requested it switches to the Inbox folder, after it downloaded new mails. This switches the view back to Mail-View.
By examining the code, I found that this does not take place, if any start page is requested in commandline.

I agree, that use of the about protocol is not the best way. You could use anything else ('calendar', 'calendar-month', 'calendar:month') - please post your ideas!
I don't know whether we could have a complete handler for a protocol like 'calendar:'...
But this would be an easy way for lots of people to start TB in Calendar view!

> Besides that, does the patch work if I do 'thunderbird.exe -P foo
> about:calendar'?

Yes, it does.