Hi Ravi,
According to my knowledge only Root objects are shown in Recent Items.
To display Access Objects ( CampaignElement ) in Recent Items I belive you need to enhance CRM_BSP_RECOBJ component and CRM_BSP_RECOBJ/RecentObjects view
and ON_HISTORY_TRIGGER method .
I debugged ON_HISTORY_TRIGGER method and I found below code which is not allowing CampaignElement to display in recent objects.
Line 37 to 40.
IF lr_current_entity->is_root( ) = abap_false.
* only root object, no dependent objects are considered
RETURN.
ENDIF.
If you skip above line of codes CampaignElement will show in Recent Object List.
Before enhancing the component ,place the debugger in above method and confirm yourself.
Also maintain in SM30 as shown
Regards
Rajarama U