custom columns (through extension api)

[TimoNotThy]

Allow making custom columns. This could either be done in a new menu or by allowing extensions to create/edit existing columns through the api.

Usecases:

* Lots of organisations work with tickets, this would allow for making a new column with  the ticketnumber for easy sorting.

* Column with the name of the alias used to send an email.

* Cut off a part of the subject that is always the same, this could be something that is used to filter the mail into a seperate folder and is of no value afterwards. It's important that this does not edit the actual subject but only its appearance in the message display list.

* Custom mail status from an external api: an example of this would be the status of a gitlab/github/... issue. As this one is more advanced I would implement this through the extension api.

To allow for sorting it should be possible to decide how new columns should be sorted, this could be alphabetically but could also be different for things like timestams.

[Jon]

Thanks for submitting an idea to the Mozilla Connect community! Your idea is now open to votes (aka kudos) and comments.

[Honza]

Thank you for reaching out. What product is the idea related to? Thunderbird?

[TimoNotThy]

@Honza, yes it's about Thunderbird 

The columns that I'm talking about are these.