+-------------+
        | List Source |  (a database proxy node)
        +-------------+
               |
               |  (key values for each list item)
               v
         +-----------+
         | Flattener |   (transforms a stack of attributes into a string)
         +-----------+
               |
               |  (pairs of formatted strings and key values) 
               v
           +--------+
           | Finder |   (a GUI proxy node for selecting from a list)
           +--------+
               |
               |  (a key value for the selected item)
               v
       +---------------+
       | Record Source |   (a database proxy node)
       +---------------+
               |
               |  (the selected record)
               v
         +-----------+
         | Edit Form |<-----------------------+  (error information)
         +-----------+                        |
               |                     +----------------+
               | (edited record)     | Message Window | (a GUI proxy node)
               v                     +----------------+
         +-----------+                        |
         | Validator |---------------------->-+  (error information)
         +-----------+ Error!
            OK |
               |  (a valid record)
               v
        +-----------------+
        | Record Injector |   (a database proxy node)
        +-----------------+