I sometimes use thunderbird offline, so I want all mails be saved locally and set settinfs such. But when I change the name or path of the folder, offline-using flag is reseted as false, so I have to re-check to use the folder offline. Procedure: 0. make sure "save all folders in this account in this computer" (in the "Synchronization and disk usage" in the account settings) checkbox is checked. (these phrases are estimation, because I don't know exact phrases in English (my thunderbird is displayed in Japanese and thunderbird doesn't provides UI locale settings) 1. make sub-folder in the inbox. 2. right-click the sub-folder, click 'properties', go to tab "Synchronization"(Sync?), see "use this folder offline" checked, and close property window. 3. right-click the sub-folder, click 'properties', change the folder name. 4. do procedure 2 and check the "use this folder offline" state (it must be un-checked). Expected: I want keep the flag unchanged.