Can I place display boxes on top of ach other?e.g. the Icon box at the top left corner, inside the picture box?
Names Default To Here( 1 ); New Window( "Example", icon Box ("Error"), Picture Box( Open( "$SAMPLE_IMAGES/windmap.png", png ) ) );
Barely. Not really supported. But What is an Alpha Channel? has an example of exactly this.
You are able to sometimes overlay some displayboxes on top of each other using margin/padding but I'm not sure if that is possible anymore. With just PictureBox you could most likely just plot the icon in the same picture?