If I forward the same message then it goes with attachment and display attachment symbol too in mai box.

I am receiving messages with text file attachment. On receiving it does not show that message is containing attachment. I am unable to see it and save as file. Even attachment symbol is not appear in mail box. If I selet from menu --> View--> Display attachment inline then attachment details display in message body. I am un able to save attached file it as a text file. If I forward the same message then it goes with attachment and display attachment symbol too in mai box. Is there any setting for incoming text attachments?