Question - In events start-of-selection is default event. When we have to use this event explicitly? Why?
Answer -
The default event in the ABAP is Start-of-selection.We have to call explicitely this event when you are writing other than ths event , that is when you write AT SELECTION-SCREEN EVENTS OR INITIALIZATION EVENT etc,you have to explicitely mention the Start-of-selection event while you are writing the logic.
Before these events called ,all the code you have written come into this default Start-of-selection screen event.