How do i add (Date: Last month) in my inbox if i deleted it.

[Blackice]

I have accidently deleted, in my (inbox) the last two options: (Date: Last
Month and Date: Older) can any one tell me how i can get them back.

 

[F.H. Muffman]

I have accidently deleted, in my (inbox) the last two options: (Date:

Last Month and Date: Older) can any one tell me how i can get them
back.

Restore the messages from the Deleted Items folder that are from last month
and older?

The only reason the group headers should disappear is if there's no mail
that fits in them.