Grids Show and Control

Hi I have two column style question First：I create a Girds one column is identity ,how can I double click this cell can open identity form? Second：Cell style is checkbox . How to setting read only ? Query  : <Item type ="Reviewer" action="get" select="_status,_cosign_role,related_id(name)"> <source_id>{id}</source_id> </Item>         Grid Column： 1.     self::Item[@type="Reviewer"]/related_id/Item[@type="Identity"]　　-->want to this cell read only and can double click 2.    self::Item[@type="Reviewer"]                       -->want to this cell read only