Oh, this is really odd. Did you know that if you have the address book open when you try to save a new calendar event, it will save the event but leave the new event dialog open, so that if you keep hitting "Save and Close" thinking it's not working, it will keep adding duplicate events without your realizing it? That looks like a bug—separate from this multiple email thing.

garretwilson said

So Thunderbird only supports two email addresses for each contact?? How can I pick up this third email address that gContactSync has brought in. Isn't a hard limit of two email addresses sort of old-fashioned? Why can't we add as many as we need? How can I work around this?

I would suggest adding the contact a second time with (Work) in they name. Most folk tend to keep work and personal information separate.

In answer to your comments. Yes, it is archaic having a hard limit, No, it is not good. Yes, there is an intention to re write the address book component from the ground up.

When Mozilla ceased development of Thunderbird in 2012 they had just begun a rewrite process. With the withdrawl of the Mozilla developers all feature updates stopped for a time while the community got organized around keeping Thunderbird alive. The first couple of years were very shoe string with Mozilla insisting Thunderbird find a new home. As you can see Thunderbird still has a Mozilla brand, so a new home was not needed in the end, but years of development disruption occurred while these issues were sorted.

With donations from the Thunderbird users a more stable situation arose, just about the time Mozilla started ripping things Thunderbird relied upon out of the development tree. So a long period of just moving the shells around occurred while the developers worked tirelessly to keep Thunderbird in a state where it would build and a new version could be released. Feature updates occurred, but they were minor.

Thunderbird 60 is the first release in a number of years with significant changes, hence the automatic disabling of add-on that have not been updated for version 60. Old versions will just not work.

Now work is finally going on in the composer and address book. with something like the cardbook add-on envisaged for the future. https://addons.thunderbird.net/en-US/thunderbird/addon/cardbook/

I have not tested it's multiple address against Lightning, but it does have a preferred address for writing mails which may well transfer to lightning.

> I would suggest adding the contact a second time with (Work) in they name.

Nooooo!!!!! :O I'm not going back to the Nokia not-smartphone days where I stored my contacts on the SIM card and made a different entry for (Home), (Work), (Fax), (Other Work), etc. (shudder)

The (already ancient) vCard RFC already has the facility to label each telephone number as home/work/whatever. No need for such a … workaround.

But thanks for the response. Essentially it sounds like a known limitation that has no hope of being resolved any time soon.