Having been an Evolution user since a few years back, I recently migrated to thunderbird and had a few "problems". Thanks to iolanda I was able to fix most of them. I post my thunderbird setup here, so I can remember when I need to setup it again.

Config Editor Settings

Always keep threads, also when changing sort preferences:

By default sort everything threaded descending by date:
mailnews.default_sort_type=22 (22 is threaded, 18 is date)
mailnews.default_sort_order=2 (1 is ascending, 2 is descending) --- there seems to be a bug here, setting it to 2 does not work and slows down thunderbird! Do not arrange threads by subject (look at msgid, references, in-reply-to, etc.): `mail.strict_threading=true` Check mail in all folders: `mail.check_all_imap_folders_for_new=true` **Dictionaries** - [Catalan](http://downloads.mozdev.org/dictionaries/spell-ca.xpi) - [Spanish](http://downloads.mozdev.org/dictionaries/spell-es-ES.xpi) - [English](http://downloads.mozdev.org/dictionaries/spell-en-US.xpi) **Add-Ons** 1) [Dictionary switcher](https://addons.mozilla.org/en-US/thunderbird/addon/3993) 2) [Disable drag and drop in the folder pane](https://addons.mozilla.org/en-US/thunderbird/addon/4591) (prevents accidentally moving folders) 3) [FolderCheck](https://addons.mozilla.org/en-US/thunderbird/addon/4936) (only useful if you don't enable check mail in all folders). 4) [Header Scroll extension](https://addons.mozilla.org/en-US/thunderbird/addon/1003) 5) [LookOut](https://addons.mozilla.org/en-US/thunderbird/addon/4433) (decode winmail.dat attachments) 6) [Sync On Arrival](https://addons.mozilla.org/en-US/thunderbird/addon/1396) (Downloads new message headers immediately when there are new messages in a folder) 7) [ThreadBubble](https://addons.mozilla.org/en-US/thunderbird/addon/5326) (resort the threaded view by date when new mail arrives) 8) [View Headers Toggle Button](https://addons.mozilla.org/en-US/thunderbird/addon/210) 9) [ThreadKey](https://addons.mozilla.org/en-US/thunderbird/addon/2299) (Use T/U keys to switch between threaded and unthreaded views). 10) [Enigmail](https://addons.mozilla.org/en-US/thunderbird/addon/71) (Sign and Encrypt/Decrypt emails using GPG) 11)[SmtpSelect](https://addons.mozilla.org/en-US/thunderbird/addon/2234) (Switch SMTP server quickly)