Proposal: MailExtensions API to allow UI overlays, but no script injection

Philipp Kewisch kewisch at
Sat Oct 12 12:41:09 UTC 2019

> On 12. Oct 2019, at 12:55 PM, ace <acelists at> wrote:
> Dňa 12. 10. 2019 o 0:20 Eyal Rozenberg napísal(a):
>>> On 12/10/2019 1:08, Geoff Lankow wrote:
>>> but having the ability to change any window and do anything to it /can
>>> not/ and /should not/ continue.
>> Why? That is a keystone feature of Thunderbird's - the fact that UI from
>> an extension code is basically on equal footing with in-app UI.
> Hi. We recently added a feature in Thundebird that allows addons to
> listen when specific windows are opened (by specifying document URLs
> they are interested in). When that happens, the addon specified code can
> run on that window. Then you could change the appearance of UI elements
> using standard DOM methods, instead of a XUL overlay file.
> See registerWindowListener() at
> This could cover some of the addon use-cases.
> aceman

Note this api isn't available to MailExtensions, just the experiments.


More information about the tb-planning mailing list