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

Eyal Rozenberg eyalroz at
Sat Oct 12 11:09:46 UTC 2019

But if that's available - what's the problem with just having those 
listeners load the relevant XUL?

If the issue is XUL vs xhtml, I'm assuming most extension authors would 
be willing to migrate their syntax toward xhtml and have that loaded. Or 
- is it something else?


On 12/10/2019 13:55, ace 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
> .

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