in your custom view, in the *ctxt class there will be one method connect nodes. i think you need to register your method for the collection wrapper of its parent. some thing looks like below
DATA: coll_wrapper TYPE REF TO cl_bsp_wd_collection_wrapper.
coll_wrapper = ME->HierarchyNode->get_collection_wrapper( ).
SET HANDLER ME->BPAssignment->on_new_focus
FOR coll_wrapper ACTIVATION iv_activate.