Adding accounting flexfield on a custom form - problem updating segment values

 I'm building a custom from which have an accounting flex field on it. What I basically have done is took template.fmb, adjusted it a bit after 11i Dev Guide and then tried to launch it against GL_INTERFACE table to check how it works against its AFF as I will need to update these values after spec.
After I query data and open the accounting FF window for update it allows me to select segment values from LOVs but when selected it doesn't update segment values.

However, I'm able to insert new rows OK on the same form through this field.