if ( vik_layer_get_interface(layer_type)->copy_item) {
subtype = vik_treeview_item_get_data(sel->vt, &iter);
vik_layer_get_interface(layer_type)->copy_item(sel, subtype, vik_treeview_item_get_pointer(sel->vt, &iter), &data, &len );
if ( vik_layer_get_interface(layer_type)->copy_item) {
subtype = vik_treeview_item_get_data(sel->vt, &iter);
vik_layer_get_interface(layer_type)->copy_item(sel, subtype, vik_treeview_item_get_pointer(sel->vt, &iter), &data, &len );