TableView.ShowFullConversations Property (Outlook)
Returns or sets a Boolean value that indicates whether to display conversation items from other folders, such as the Sent Items folder, as part of the conversation in the table view. Read/write.
The ShowFullConversations property takes effect only if the current table view displays items by date and conversation.
True indicates that items of the same conversation are displayed by default as part of the conversation in the table view. False indicates that only conversation items in the current folder are displayed in the table view.
The ShowFullConversations property is analogous to selecting Show Messages from Other Folders in the Conversations menu of the Arrangement group on the View tab of the ribbon.