Unlike Inline Operations which cause a new change (also known as a Comment) to be added to an existing TMail, Forking Operations cause a new TMail to be created.

TMail is different from Email in this regard. All operations in EMail such as Reply, Reply All and Forward can be considered Forking Operations. This is because they all create a new EMail. There is no equivalent in EMail of Inline Operations. A large part of the power of TMail derives from the ability to add Comments to an existing TMail via Inline Operations.