drag_set_icon_widget

function drag_set_icon_widget(context:Gdk.DragContext, widget:Gtk.Widget, hot_x:Number, hot_y:Number):void {
    // Gjs wrapper for gtk_drag_set_icon_widget()
}

Changes the icon for a widget to a given widget. GTK+ will not destroy the icon, so if you don't want it to persist, you should connect to the "drag-end" signal and destroy it yourself.

context: the context for a drag. (This must be called with a context for the source side of a drag)
widget: a toplevel window to use as an icon.
hot_x: the X offset within widget of the hotspot.
hot_y: the Y offset within widget of the hotspot.