Mozilla plans to ship Lightning add-on with Thunderbird 38 email client
Thunderbird is the main email client that I use on all desktop systems. There are plenty of reasons for that, from full control over all emails to better privacy and options to load add-ons that improve the functionality of the client.
One of the most popular add-ons for Thunderbird is the calendar extension Lightning. Thunderbird itself does not ship with a calendar of its own while email clients such as Microsoft's Outlook do ship with one.
Lightning is regularly updated and there have been talks in the past to integrate it natively in the email client. The original plan was to integrate the calendar in Thunderbird 3 and then later on in Thunderbird 8 but the decision was overturned each time.
The integration never happened and the reasons given at the time were that Mozilla did not have enough resources to maintain the email client and Thunderbird, and that it was not well performing.
It appears that the community development team made the decision to ship the Lightning add-on with Mozilla Thunderbird 38 which will be released on March 19th, 2015.
The core reason for the change of heart was Mozilla's decision to hand over development of the email client to the community, that modern email clients are expected to support a calendar, and that efforts are underway to make it easier to match Lightning to specific versions of the Thunderbird client.
So how will it be integrated?
The plan is to ship Thunderbird 38 with the Lightning extension. As it stands now, Lightning will not be enabled on systems where it has not been installed before. The reason for this is that it may impact the performance on systems if activated and that it does not make sense to enable it on systems where it is not being used yet.
Nothing will change for users who are using the Lightning extension already.
Note that it is possible for the plan to be overturned in the future or that changes are implemented. This article will be updated when that happens so that you are always in the know in this regard. (via Sören)
Now You: What's your take on this? Good move or would you prefer a different solution?

You said that Outlook isn’t your main email client, so which is your main one?
I think its thunderbird
It is Mozilla Thunderbird.
Awesome! This actually solved my problem… what a stupid bug.
If this is the same bug that I’ve encountered, there may be another fix: (1) hover over open Outlook item in Taskbar, cursor up to hover over Outlook window item, and right-click; (2) this should give you Restore / Move / Size / Minimize / Maximize — choose Move or Size; (3) use your cursor keys, going arbitrarily N/S/E/W, to try to move or size the Outlook window back into view. Basically, the app behaves as though it were open in a 0x0 window, or at a location that’s offscreen, and this will frequently work to resize and/or move the window. Don’t forget to close while resized/moved, so that Outlook remembers the size/position for next time.
THANK YOU Claude!!! I could get the main window to launch but could not get any other message window to show on the desktop. You are my hero!!!!
Solved my issue! 6 years later and this is still problem…
Fantastic. Thank you. Size did the trick.
This solved my Outlook problem, too. Thank you. :)
Thank you so much, this started happening to me today and was causing big problems. You are a life saver, I hope I can help you in some way some day.
You are a god – thank you!
thanks a lot…. work like charm.. :-)
Yah…thanks Claude. I’ve been having the same problem and tried all the suggestions…your solution was the answer. It had resized itself to a 0/0 box. Cheers
Excellent post. This had me baffled even trying to accurately describe the problem. This fixed it for me.
Thank you
Thanks a lot for the article. Don’t know why it happenend, don’t know how it got fixed, but it was really annoying and now it works :-)
Thanks a lot. I was facing this issue from past 3 week. I tried everything but no resolution. The issue was happening intermittently and mainly when I was changing the display of screen ( as i use 2 monitors). The only option i had was to do system restore. But thanks to you.
I’ve been tried to sole this problem for 12hours. Your comment about changing the display of screen helped me a lot!! Thanks!!
Thank you…don’t know why this happened but your instructions helped me fix it. Running Windows 10 and office pro 2007
Great tip! Thanks!
Worked for me, too – thank you!!!
It’s Worked for me, too
thank you very much!
I had a similar issue with Outlook 2013 on Windows 10 and this helped me to fix it. Thank you very much!
Thank you so much. Solved!
Considering you published this in 2012, incredible not been debugged by Microsoft.
Thank you again. M
This problem was faced by only one user logging to TS 2008 r2 using outlook 2010.The issue was resolved.
Thanks.
Great tip. Thank you!!!! If it helps, I had to use the Control Key and the arrow keys at the same time to bring my window back into view. Worked like a charm.
Thank you, this worked !!!!
Man, you are a fucking god. Thanks a lot, what an annoying bug!!
Awesome, this post solved the issue. Many thanks!