gtk:drag-dest-set-proxy (widget window protocol coordinates)

widget -- a gtk:widget object
window -- a gdk:window object to which to forward drag events
protocol -- a gdk:drag-protocol value with the drag protocol which window accepts, you can use the gdk:drag-context-protocol function to determine this
coordinates -- if true, send the same coordinates to the destination, because it is an embedded subwindow

Sets the widget as a proxy for drops to another window. The gtk:drag-dest-set-proxy function has been deprecated since version 3.22.