Mbol add to flange Boltref.....

Hi friends,

When I add Mbol to flange boltref by catview , I have error and can not modify item again, error message is :"(2,201) Element Mbolt/ISBBN-BT does not have attribute LENG." Is it normal or i have wrong...?

MBOLs do not have an attribute LENG just an Sbrarray  (list of SBOLs)
SBOLs have an attribute LENG

I have the same problem and really dont know why this occurs.