Header Regex not working as expected, using "From:/regular expression/"

[RealRaven2000]

We now would expect people to use the parameter "Sender: " for the Header Regex, such as in the following example:

Sender:[.\-_*«"“#]{0,13}ventas[.\-_*"”» #]{0,13}<

However a user has also used "From:" instead, in conjunction with the Add-on lookout-fix, but he had to append the | character top make the regular expression work.

Goal: find out why (and how) from works in this case and either make it work for everyone or at least fix the "pipe character" issue. We will also contact the lookout author to get their opinion on this or possibly make a fix.

It would also be interesting to know when "From:" stopped working (my guess is Thunderbird 115) as it is not listed as a property of the message header that's being passed to all search items by the Thunderbird filter service when filtering.

The user was able to make it work with From: (and lookout-fix enabled) using:

From:[.\-_*«"“#]{0,13}ventas[.\-_*"”» #]{0,13}<|

[RealRaven2000]

I did some tests trying to reproduce the issue by installing the latest LookOut (fix version) from ATN and then using the expression

From:[.\-_*«"“#]{0,13}ventas[.\-_*"”» #]{0,13}<|

as suggested by the reporter of the bug, but it cannot find a "from" header, so there is no regular expression match happening.

List of other Add-ons installed by the OP:

Compact Headers    extension    5.4    true    compactHeaders@dillinger
Deselect on Delete TB78    extension    3.7    true    [deselectondelete@baz.pw](mailto:deselectondelete@baz.pw)
DuckDuckGo    extension    1.0    true    [ddg@search.mozilla.org](mailto:ddg@search.mozilla.org)
EML-Editor    extension    1.8    true    [elm-editor@dyrk.org](mailto:elm-editor@dyrk.org)
FiltaQuilla    extension    4.0b2    true    [filtaquilla@mesquilla.com](mailto:filtaquilla@mesquilla.com)
LookOut (fix version)    extension    6.2    true    lookout@s3_fix_version
Mail Merge    extension    10.4.0    true    [mailmerge@example.net](mailto:mailmerge@example.net)
SubSwitch    extension    0.9.62    true    {957509b1-217a-46c7-b08b-f67d08d53883}
Xpunge    extension    4.0.2    true    {786abda0-fd14-d247-bf69-38b2fc18491b}
X-Unsent support    extension    4.0.1    false    X-Unsent_support@pl

I also tried installing the DuckDuckGo Privacy extension from https://duckduckgo.com/ but that didn't make any difference. (this may not be the one that is listed above). tried x-unsent support as well (4.0.1) but alos no change in behavior.

[dugite-code]

It should be very unlikely lookout would be the cause of any issues regarding search or email headers. We went through a recent re-write and are only doing non-destructive modifications regarding the display of attachments.

Perhaps it's the emails themselves, given we are dealing with Microsoft's TNEF emails and they play by their own rules.