The information message The diagram had no layout information and has been laid out automatically. Please save changes in order to keep this layout. informs user about need to save diagram to preserve this feature result. However on my machine is this message show less than 2 seconds what is short time to read whole message.

We should increase the time the message is shown to enable the user read whole message. Furthermore, we should mark designer as dirty if the automatic layout feature was applied to indicate more some changes need to be saved.