Thunderbird Android 20.1: Manage folders opens another IMAP account's folders, preventing custom-folder sync

Checklist

• I have used the search function to see if someone else has already submitted the same bug report.
• I will describe the problem with as much detail as possible.

App

Thunderbird for Android

App version

20.1

Where did you get the app from?

None

Android version

16

Device model

Samsung Galaxy S25 Ultra

Steps to reproduce

1. Configure multiple separate IMAP accounts.
2. Select Account A in the account drawer.
3. Confirm that the drawer correctly shows Account A and its custom folders, including Blog and Social.
4. Select Manage folders.
5. Observe that the displayed custom folders belong to Account B, not Account A.

The default folders make this easy to miss because they exist in both accounts. The custom folders clearly identify the wrong account.

Removing and adding Account A made the folder list correct only temporarily; after further use or restart it again showed Account B's folders.

Expected behavior

Manage folders must show only the folders of the account selected in the drawer. Changes to Sync and Push must apply to that same account and remain correctly associated after restarting the app.

Actual behavior

Manage folders can be associated with a different account than the one selected in the account drawer. This prevents safely enabling Sync or Push for Account A's actual custom folders. Messages moved by server-side rules into Blog and Social are then not reliably synchronized or notified.

Sanitized debug-log evidence:

• Each affected account has a 15-minute automatic check interval and background operations set to Always.
• The recorded state is folderSyncMode=FIRST_CLASS and folderPushMode=NONE.
• A manual Sync account connected successfully and scheduled only syncINBOX; it did not schedule Blog, Social, or other custom folders.
• No IMAP authentication, TLS, or network error occurred.

The sync and push modes may be valid defaults, but this account-association failure prevents changing settings for the correct folders. Inbox can be checked successfully while mail routed into custom folders is not checked in the background and does not generate reliable notifications.

Logs

No log attached for privacy. The sanitized diagnostic evidence is included above.

Start by tracing the Manage folders flow from the account drawer and compare which account supplies the displayed custom folders and Sync/Push settings. Reproduce the issue with two IMAP accounts, then verify that the selected account's folders remain associated correctly after changing settings and restarting the app.