Thunderbird Encrypted Subject
Here are specific guides for the Thunderbird email client. To configure Thunderbird for certain providers, please check out their separate pages.
Disable subject encryption
The newer Thunderbird versions do not only encrypt the mail body but also its subject line. In many other email clients, that leads to "..." subjects.
Here's how you can disable that and thereby be more compatible and pleasant for people using other email clients.
Go to Thunderbird's preferences via Edit > Preferences
Scroll to the bottom and find the button Config Editor. You can also search for it.
- If you're asked to be careful, confirm
In the new window titled with about:config, search for protectSubject
For all found lines (could be one or more), double-click them until the Value column is set false.
Here is how it should look like: