Hi Ram,
Yes there are multiple areas to complete this through implicit enh.
However for the next requirement you need to trigger a round trip for the event, I found that this scenario is only possible in case the search fields are grouped together ( adding multiple lines of same search criteria ) .
This is here in class CL_THTMLB_ADVANCEDSEARCH , method : IF_BSP_ELEMENT~DO_AT_BEGINNING
IF LT_CAN_CREATE_GROUPING IS NOT INITIAL
AND LV_CURRENT_CRIT_INDEX IN LT_CAN_CREATE_GROUPING.
* ...we need to have a server-side event on operator change so
* the backend can recalculate and re-render the new grouping
LV_ON_OP_SELECT = 'thtmlbGroupScenarioOperatorChange'.
ELSE.
CLEAR LV_ON_OP_SELECT.
ENDIF.
Here LV_ON_OP_SELECT marks the event to be triggered but you can see that it won't trigger for any other cases. So something needs to be done here.
/Hasan