My IMAP account has "Move deleted mails to trash and expunge immediately" activated. When I'm offline and move messages to another folder, they get a blue arrow. When going online, I should be able to run tools/execute to get them actually moved. The tools/execute menu item is disabled. Only when I deactivate "Move deleted mails to trash and expunge immediately", the menu item gets active.
The option, "Move deleted mails to trash and expunge immediately", was removed some time ago.