Custom window titles disappear after session is restored and a new tab added.

[ElhemEnohpi]

Short description

Custom window titles set with the Window Titler addon are saved. When they are restored, the window appears at first with the custom title, but it doesn't show in the Window Titler menu. As soon as a new tab is added to the window, the custom title disappears and is lost.

Steps to reproduce

1. Start browser with clean profile
2. Install Tab Session Manager
3. Turn off Auto Save
4. Install Window Titler, and add a custom window title.
5. Manually save the current window as a session.
6. Note that the session's tab list has the custom title in square brackets.
7. Keep the original window open, and restore the saved session.
8. Note that the restored window has the custom title in square brackets, but that it's not shown in the Window Titler menu.
9. Add a new tab to the original window, and confirm that it still has the title.
10. Add a new tab to the restored window.

Expected result

The window continues to have the custom title.

Actual result

The window no longer has a custom title. If the session is saved again, no custom title is saved.

Platform information

• Platform (OS): macOS 12.1
• Version of browser: Firefox 95.0
• Version of Tab Session Manager: 6.11.1

Additional context

I think this started happening fairly recently, maybe sometime in the last month or so. It used to work ok in the past.

[sienori]

In Firefox, TSM supports window title restoration but it may be unstable...

[theAkito]

Not sure, if the fix for this issue would fix my issue, as well.

I use the FireTitle extension for Firefox to prefix titles to each window.

Those titles are always lost, when a window is restored. It's not related to adding a tab after backup or restoration.