Support duplication of foreign nodes.

editor/scene_tree_dock.cpp

@@ -680,10 +680,6 @@ void SceneTreeDock::_tool_selected(int p_tool, bool p_confirm_override) {
 				break;
 			}
 
-			if (!_validate_no_foreign()) {
-				break;
-			}
-
 			List<Node *> selection = editor_selection->get_selected_node_list();
 			if (selection.size() == 0) {
 				break;
@@ -703,7 +699,15 @@ void SceneTreeDock::_tool_selected(int p_tool, bool p_confirm_override) {
 				Node *parent = node->get_parent();
 
 				List<Node *> owned;
-				node->get_owned_by(node->get_owner(), &owned);
+				Node *owner = node;
+				while (owner) {
+					List<Node *> cur_owned;
+					node->get_owned_by(owner, &cur_owned);
+					owner = owner->get_owner();
+					for (Node *F : cur_owned) {
+						owned.push_back(F);
+					}
+				}
 
 				HashMap<const Node *, Node *> duplimap;
 				Node *dup = node->duplicate_from_editor(duplimap);
@@ -723,9 +727,10 @@ void SceneTreeDock::_tool_selected(int p_tool, bool p_confirm_override) {
 						continue;
 					}
 					Node *d = duplimap[F];
-					undo_redo->add_do_method(d, "set_owner", node->get_owner());
+					undo_redo->add_do_method(d, "set_owner", edited_scene);
 				}
 				undo_redo->add_do_method(editor_selection, "add_node", dup);
+				undo_redo->add_do_method(dup, "set_owner", edited_scene);
 				undo_redo->add_undo_method(parent, "remove_child", dup);
 				undo_redo->add_do_reference(dup);