Transient Attribute not updating the value from dropdown ADF

• One reason could be List of Values doesn't match the type of the Attribute in Transient View Object ( Type Mismatch )
• Make sure you update Transient Attribute as "Always" updatable

Groovy Expression to get SUM of a column in View Object Attribute ADF

Don't forget to create a ***'View Accessor' to itself and use sum keyword  and attribute name in "in double quotes" ("Attribute Name") in the expression field of the transient attribute

http://www.techartifact.com/blogs/2012/11/adf-groovy-for-total-sum-of-a-column-in-a-table.html#sthash.BHFcG13w.dpbs