How knows how to detect drop on web zone?

To write emails, I use TinyMce in a web zone, work like a charm.
But I’m writing a picture’s browser, and I want to place a picture by drag&drop.

It works on a drop to a button (with my 4D code), but to catch the drop event on a web zone to place my code as well ? Without going into js development ?

[]34221846;“Left the editor, right the palette based on 4D Pop Resources Buddy…”[/]