begin
ListBox1.OnViewportPositionChange := ViewPortPositionChange;
ListBox2.OnViewportPositionChange := ViewPortPositionChange;
end;
procedure TForm2.ViewPortPositionChange(Sender: TObject; const OldViewportPosition,
NewViewportPosition: TPointF; const ContentSizeChanged: Boolean);
begin
if (Sender as TListBox).Name = 'ListBox1' then
ListBox2.ViewportPosition := NewViewportPosition
else
ListBox1.ViewportPosition := NewViewportPosition;
end;