Oracle Forms

hi all,
i am using
Forms [32 Bit] Version 6.0.8.24.1 (Production)
Oracle Database 10g Release 10.2.0.1.0 - Production
i have a multi record block each block contains a button(button is to approve the record in terms of changing the status)
i have the items like date,remarks and button
the button should be enabled if the remarks is not null otherwise it should be disabled.
for this in pre-record trigger i have written

if :record is null then
   set_item_property('button',enabled,property_false);
else
      set_item_property('button',enabled,property_false);
end if;

what problem is enable and disable is impacting on all the buttons in the block. in other words if first record's remarks is null then all the records button is disabled. if first record's remarks column is not null then all the records of the button column is enabled.
i have to make enable and disable the button for the corresponding record.that means if first record's remarks column is not null then only first records button should be enabled others should be disabled.

Thanks..