If enabled then the messages are not only grouped according to special information included in the messages but also according to their subject, & ie; messages with the same subject are considered as being related. If many messages are threaded below unrelated messages then you might want to disable this option.
Se isto estiver activo, as mensaxes agrúpanse non só de acordo coa información especial que se inclúe nas mensaxes mais tamén de acordo co seu asunto, & ie; considérase que as mensaxes co mesmo asunto están relacionadas. Se hai moitas mensaxes enfiadas por baixo de mensaxes sen relación, será mellor que desactive esta opción.