Betterbird

Whilst the screenshots are not a mock-up, they are from WIP code (which I forgot to mention in the commit message). Further checkins will follow, including fixing the expand/collapse behaviour,...

> Question - how does this behave when collapsed? i.e is it still going to be the original/oldest message shown in the messages list pane? Is there a way to...

Here's what we have so far. We'll fix the chevron/twisty direction and the connecting lines. https://github.com/user-attachments/assets/8b6d3bca-02cc-41e5-ab56-ceee33f494a2

Update thread lines. Chevron/twisty will follow: 

This is complete now, you can try it in BB 128 for Windows: https://www.betterbird.eu/downloads/get.php?os=win&lang=en-US&version=future We're still considering whether it's worth the effort to backport to BB 115. See the [Downloads](https://www.betterbird.eu/downloads/)...

BB 115 backport: https://www.betterbird.eu/downloads/WindowsInstaller/betterbird-115.13.0-bb30-latest-build3.en-US.win64.installer.exe Now: https://www.betterbird.eu/downloads/WindowsInstaller/betterbird-115.13.0-bb30-latest-build4.en-US.win64.installer.exe

Hmm, works if nothing moves, but new messages don't get put into the right spot. Should be fixable.

This is turning our to be a nightmare. There are so many places in the code which assume that thread children are underneath the thread parent and that collapsing or...

Update: So reversed threading works when lightly tested in "normal" folder views, quick filter views, and virtual folder views (unified/search folders). It doesn't work in "search" views so far, so...

This should work well enough now, please try one of these builds: https://www.betterbird.eu/downloads/128-Preview/betterbird-128.0.1esr-bb5-build7.en-US.win64.installer.exe https://www.betterbird.eu/downloads/WindowsInstaller/betterbird-115.13.0-bb30-latest-build10.en-US.win64.installer.exe https://www.betterbird.eu/downloads/LinuxArchive/betterbird-115.13.0-bb30-latest-build10.en-US.linux-x86_64.tar.bz2 Please take a look at the [release notes](https://www.betterbird.eu/releasenotes/) for details. EDIT: Those builds no longer...