summary threading, repeated subjects

[Nicolas KOWALSKI]

Hello,

>From time to time, in the summary buffer the threading shows repeated
subjects, instead of leaving them empty. Here is an example:


O  [Tom Lane          ]    `->  Re: [GENERAL] postgre vs MySQL
O  [Greg Smith        ]     +->
O  [Justin            ]     `->  Re: [GENERAL] postgre vs MySQL
O  [Scott Marlowe     ]      `->
O  [Justin            ]       +->
O  [Russell Smith     ]       `->
O  [Scott Marlowe     ]        +->
O  [Greg Smith        ]        `->
O  [Glyn Astill       ]         `->
O  [Bruce Momjian     ]          `->
O  [Joshua D. Drake   ]           +->
O  [Glyn Astill       ]           `->
O  [Tom Lane          ]            `->  Re: [GENERAL] postgre vs MySQL
O  <Alex Turner       >             `->  Re: [GENERAL] postgre vs MySQL


How can I prevent this ?

My summary format for the mailing-lists I am subscribed to is defined
with gnus-parameters:

(setq gnus-parameters

   ;;
   ;; All mailing-lists
   ;; use a simpler (no size/date) summary line format
   ;; expire old mails
   ;;
   ("^nnimap:list"
    (gnus-summary-line-format "%U%R%z%(%[%-18,18f%]%) %*%B %s\n")
    (total-expire . t)
    )
   
 )


Thanks,
-- 
Nicolas