Here is my last attempt. Press F3 (or any key, you parameter in ini. file) to display/hide all events. Also after the hero activates event, it will be deleted from display list.
Still problems:
a) UN:O does not recognize objects placed on events, so I had to create 64x64 graphic, and place it on the square south from event. (v2+1) then delete yellow square and make it passable. This way I can delete it later by specifying that bottom square.
b) But if on this square there is one hero, game will crash, so I had to check if any hero there then exit, so in this particular condition, delete script will be ignored
c) If two events are adjacent perpendicular (v2 and v2+1), the bottom will be ignored from delete list (because the problem aforementioned).
Any better ideas on how I could achieve such thing?