How to set up a chain campain ?

Hi there,

In a sent campain (more than 4 weeks), I can see for example a 30 "non opened" list
As I create a chain campain, it doesn't check these 30, witch turned to "0" "non opened"

After reading the help senter...I think there is smg I'm doing the wrong way...
Any greatfull help ?
Many Thanks. Denys.