Gmail enabled swithing between threaded conversation and classic views. When classis view is enabled, messages are no longer grouped in one conversation but stand alone.

Google Apps editions supporting this feature:
Standard, Premier, Education, Team and Partner editions

Languages supported in this feature:
All languages supported by Gmail

How to access these new features:
– enabled only for domains with activated pre-release function
– in Gmail Settings, open”Conversation view”, click on your choice and save