In new installations of this addon, when using HTML in a template, the feature
to "Replace line breaks with <br>" is enabled even though it is not checked.
Checking and then unchecking the option properly turns it off.

This applies to all types of messages (write/reply/forward), and each has to be
checked/unchecked to fix.

I have duplicated this issue on 2 machines. One linux, one Mac OS-X.
SmartTemplate4 0.9.4
Thunderbird 17.0.8 on OSX, 17.0.6 on Linux.

(In reply to comment #0)
> In new installations of this addon, when using HTML in a template, the feature
> to "Replace line breaks with <br>" is enabled even though it is not checked.
> Checking and then unchecking the option properly turns it off.
> 
> This applies to all types of messages (write/reply/forward), and each has to be
> checked/unchecked to fix.
> 
> I have duplicated this issue on 2 machines. One linux, one Mac OS-X.
> SmartTemplate4 0.9.4
> Thunderbird 17.0.8 on OSX, 17.0.6 on Linux.
> 

Looking at the still quite dreadful mess that the original source code was, I
am coming to the conclusion that the default setting is indeed (as you pointed
out) to replace line breaks with <br>. There is a function called setPref1st
which sets missing preferences when they are not found, and this sets:

extensions.smartTemplate4.newnbr = true
extensions.smartTemplate4.rspnbr = true
extensions.smartTemplate4.fwdnbr = true

however maybe this is only called when you open the options window and / or
select a different identity for the first time. It seems to be not called if
you choose to use st4 without configuring it. However, since the function is
called on the Load event of the options window this should be reflected in the
UI, so I need to do some additional tests why it doesn't show on your setup. My
guess is that the load event fires too late and the preferences are already
read at that stage. 

If this is the case, I also need to investigate whether there is an economical
way of updating the preference-bound UI without doing it manually for each and
every element.

I also have the same problem.
When configuring a new account , i have to place the signature template with
option checked, and try to make a new email, reply and forward.
Thane came back to smarttemplate definitions and unmark each one.
Then it is going to work fine.
Is a lot of courso the get it working at first time.... If you can get the
process easy it would be awesome.

An old bug, apparently it was fixed but came back to bite me in THunderbird 52.
It's back with a vengeance so I am trying to fix it for good this time...

Created an attachment (id=8281) [details]
SmartTemplate 1.5 pre 26

Fixes the bug even when "Use Common" check box is used.

Setting to Resolved Fixed with officially Release 1.5