void frm_main::Paint(Draw& w) {
  Size sz = GetSize();
  w.DrawRect(sz, Yellow()); // System draw, background = yellow.
  ImageBuffer ib(sz);
  BufferPainter bp(ib, MODE_ANTIALIASED);
  bp.Clear(RGBAZero());     // Buffer now has transparent background.

  _icons_paint(bp, scroll.Get().x, scroll.Get().y, allow_scaling, render_everything);
	
  if(show_overlay) {
    _paint_overlay(bp);
  }

  SetSurface(w, 0, 0, sz.cx, sz.cy, ~ib); // You need to use SetSurface to directly paint buffer content here (this is optimized for systemdraw (possibly faster than usual image drawing) ...
}