Thunderbird question

[marty60]

In utils/userChrome.jsm this code apparently lets us create script buttons on the main Thunderbird toolbars using this code:

let _uc = {
ALWAYSEXECUTE: 'rebuild_userChrome.uc.js',
BROWSERCHROME: AppConstants.MOZ_APP_NAME == 'thunderbird' ? 'chrome://messenger/content/messenger.xhtml' : 'chrome://browser/content/browser.xhtml',
BROWSERTYPE: AppConstants.MOZ_APP_NAME == 'thunderbird' ? 'mail:3pane' : 'navigator:browser',

If you change 'chrome://messenger/content/messenger.xhtml'

to

'chrome://messenger/content/messageWindow.xhtml'

then the buttons will appear on a message toolbar if it’s a separate window provided the script button is also written as “location == "chrome://messenger/content/messageWindow.xhtml”.

Is there a way to change the code in userChrome.jsm so that the buttons are able to appear on all toolbars? There may be instances where script buttons are needed for the addressbook or messengercompose as well as the message bar. I’ve tried using different variables to no avail.

Thanks for any assistance.