Bug 428303

Summary:	Threading Broken When Using Clone of Standard Mailing List
Product:	[Applications] kmail2	Reporter:	Garry Williams <gtwilliams>
Component:	message list	Assignee:	kdepim bugs <pim-bugs-null>
Status:	REPORTED ---
Severity:	normal
Priority:	NOR
Version First Reported In:	5.13.2
Target Milestone:	---
Platform:	Other
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description Garry Williams 2020-10-26 20:54:03 UTC

SUMMARY
Message threading is broken when using a clone of Standard Mailing List Aggregation.

Threading is flawless all the time when using Standard Mailing List Aggregation.  Clone the aggregation and now new messages sometimes do not end up threaded correctly and look like a new thread altogether.

All attributes are identical to shipped Standard Mailing List Aggregation.

As an aside, creating a brand new Aggregation with identical attributes also results in broken threading.  It seems the only way to get flawless threading is to use the built-in Standard Mailing List Aggregation.


STEPS TO REPRODUCE
1. Clone Standard Mailing List Aggregation
2. Select Clone for aggregation
3. 

OBSERVED RESULT
Some messages do not appear in their correct threads and end up being thread leaders instead.


EXPECTED RESULT
Threading works as with the Standard Mailing List Aggregation.  (Since the clone is identical in every respect that can be known from the UI.)

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Fedora 5.8.16-200.fc32.x86_64, kmail kmail2 5.13.2 (19.12.2)
(available in About System)

KDE Frameworks 5.73.0
Qt 5.14.2 (built against 5.14.2)
The xcb windowing system
plasma-desktop-5.18.5-2.fc32.x86_64


ADDITIONAL INFORMATION
This has been broken for quite a while now.  I do not know when it was introduced.

I want to clone Standard Mailing List because I want threads expanded all the time.  That option is not set in the shipped Standard Mailing List Aggregation and it cannot be changed without cloning a new Aggregation.