EVENTS IN INTERACTIVE REPORTS:
1.initialization
2.at selection screen
   2(A).at selection-screen on <field>
   2(B).at selection-screen output
   2(C).at selection-screen on value request for <field>
3.start-of-selection.
4.top-of-page
5.end-of-page
6.top-of-page during line-selection
7.at line-selection
8.at user-command