Postbox displays messages in the Thread Pane by conversation. Each conversation is comprised of a Summary Row, with individual message threads displayed below. When the Summary Row is selected, Postbox displays messages as a single, chronological conversation.
By default Postbox will display all messages related to the current conversation from all folders, such as the Inbox, Sent, and Archive folder. To only display messages from the current folder, select Preferences from the Postbox menu (or on Windows, Options from the Tools menu), click the Display icon and then the Conversations tab, and then select the Only from the current folder radio button.
Turning Off Profile Photos When Reading Messages
To stop showing conversation photos when reading messages , select Preferences from the Postbox menu (or on Windows, Options from the Tools menu), click the Display icon and then the Conversations tab, and then uncheck the Include contact photos for each participant in the conversation checkbox.
Controlling Which Messages Are Opened Automatically
When selecting a conversation in the message pane, Postbox automatically expands all of the unread messages and up to 3 additional messages. You can control the number of additional messages that are expanded by opening the config editor, type in pb.conversation_display.max_open_messages and double click pb.conversation_display.max_open_messages to change the number. For instance, changing the number to 0 would cause only the unread messages in the conversation to be automatically opened similar to gmail.
Warning: changing pb.conversation_display.max_open_messages to a value larger than 10 will cause performance issues with slow message loading times. We don't recommend you make it any larger than 10.
Disabling Conversation View
To disable conversation mode for a particular folder, go to View | Threads and uncheck Organize By Thread. To disable conversation view for all folders including new folders, open the Config Editor and type in: mailnews.default_view_flags. Double click that entry and change the value to 0. You may still need to go through the View menu to turn off conversation mode on existing folders after changing that preference.