YaST does not remember my password !

Hi there ! Merry Christmas to all ! I am wondering why YaST does not remeber my password when I launch it. At lauch, a new Frame appears (KDE su) in order to put the root password. I check the Checkbox (remeber the password) but when I restart Yast the field is always empty, like the password is not remembered. Is is a bug or a security feature ? Arnaud