Hi Madan,
in your activity view place the cursor on any one of the field and click on alt+shift+f2 then you will get hierarchy list like this..
in that click on overview page identify the component name.
go to that component and GET_STATE_DESCRIPTION there is already predefined code exists that code will display the selected text so you have to manipulate that code and display accordingly.
In my previous link i have pasted some code to display transaction no and text.
DATA:
lr_entity TYPE REF TO if_bol_bo_property_access,
lv_tran.no type CRMT_OBJECT_ID.
lr_entity = me->typed_context->btadminh->collection_wrapper->get_current( ).
CHECK lr_entity IS BOUND.
description = cl_crm_uiu_bt_tools=>get_title_header( lr_entity ).
lv_tran.no = lr_entity->get_property_as_string( iv_attr_name = 'transaction.no' ).
you have to get that transaction no.
CONCATENATE lv_tran.no '/' description INTO description SEPARATEDBY space.
this is the way based on that you have to manipulate according to your requirement.
Thanks & Regards,
Srinivas.