TB Mailextension help needed TB 64

Thunderbird Add-ons
#1

I am working on a TB WebExtension extension.
I want to add a listener to respond whenever a compose window opens.

I looked at the Owl webextension or Mailextension and it looks like I should be able to use the code that I used in my bootstrapped extension which used Services.
But as soon as I add
ChromeUtils.import(“resource://gre/modules/Services.jsm”);
to the extension it dies. This line was copied from the owl extension. :face_with_raised_eyebrow:

Any help very welcome. :smile:
Blessings
Graeme