(In reply to marco from comment #17)
> Same problem in Windows.
> To get the calendar working I searched a very old version of Thunderbird
> 9.0.1 + Lightning 1.1.1 : it works perfectly, but this is not a solution!
Not a solution, but a hint. Somewhere between then and now (or first report of the bug), it broke. If you can work with some people on in between versions, it might be further narrowed down and identified. This is why it is nice having a large base of "testers" looking at these programs. Without "testers", developers would have no feedback on the product.
(In reply to marco from comment #17)
> Same problem in Windows.
> To get the calendar working I searched a very old version of Thunderbird
> 9.0.1 + Lightning 1.1.1 : it works perfectly, but this is not a solution!
Not a solution, but a hint. Somewhere between then and now (or first report of the bug), it broke. If you can work with some people on in between versions, it might be further narrowed down and identified. This is why it is nice having a large base of "testers" looking at these programs. Without "testers", developers would have no feedback on the product.