Tb115 - account template not loaded when changing From address

[RealRaven2000]

When selecting a different identity, the new one isn't selected in SmartTemplates 4.1. instead we see the following error log:

Uncaught (in promise) TypeError: this.smartTemplate is undefined
    loadIdentity chrome://smarttemplate4/content/smartTemplate-main.js:741
    LoadIdentity chrome://messenger/content/messengercompose/MsgComposeCommands.js:9533
    oncommand chrome://messenger/content/messengercompose/messengercompose.xhtml:1
smartTemplate-main.js:741:11

[RealRaven2000]

It appears that the new event handler "compose-from-changed" calls SmartTemplate4.loadIdentity() with the wrong context. "this" evaluates to ChromeWindow chrome://messenger/content/messengercompose/messengercompose.xhtml and not to the SmartTemplate4 instance of the script. This can be changed by binding a different context in the event listener.

  // old code
  window.addEventListener("compose-from-changed", SmartTemplate4.loadIdentity);
  // new code:
  window.addEventListener("compose-from-changed", SmartTemplate4.loadIdentity.bind(SmartTemplate4));

After fixing that, on top of that I am still having problems when detecting the change - because changing the identity during LoadIdentity() in core sets the gMsgCompose.bodyModified flag:

this is a problem because I do not allow changing the mail text if it was already modified (in my mind, this flag is / should be reserved for the user having edited the email)

[RealRaven2000]

Ok, here is the bigger picture:

the problem is exactly when I would need the bodyModified flag to tell me the truth it pretends that the email was edited. I need to follow the triggering of this and load the identity template but need to know that this event was caused by Thunderbird's LoadIdentity function and nothing else. I will search the Core database to see whether it is being triggered from anywhere else.

[RealRaven2000]

Just playing this through - Thunderbird (I believe falsely) also resets the bodyModified flag in this case after the user has done edits. I don't think it should do this, it should store the previous bodyModfied state and restore it at the end of LoadIdentity(). Ideally it should do that before dispatching the compose-from-changed event

[RealRaven2000]

Since I cannot determine reliably whether the body was modified when the user changes the identity, I have decided to prompt them:

Clicking OK will discard anything that was written by the user since composer started, Cancel will leave the contents of the email unchanged (It may swap the signature out though).

smartTemplate-fx-4.1.1pre10.zip

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To install the preview version above, please download the zip file and then drag the file into Thunderbird Add-ons Manager. Do not extract file contents, as they won't install.

[RealRaven2000]

Implemented in 4.2.1, published 25/09/2023