I am usoing CL_SALV_TREE class for displaying the tree. I have registered the event double click.
data: lr_events type ref to cl_salv_events_tree.
lr_events = tree->get_event( ).
set handler at_double_click for lr_events.
Double click is gettting triggered, but, as it is not raising an application event, its not calling the PAI/PBO of screen for the futher screen processing.