property remove parent owned nodes when using replace, fixes #4128

scene/main/node.cpp

@@ -2081,6 +2081,10 @@ void Node::update_configuration_warning() {
 
 }
 
+bool Node::is_owned_by_parent() const {
+	data.parent_owned;
+}
+
 void Node::_bind_methods() {
 
 	ObjectTypeDB::bind_method(_MD("_add_child_below_node","node:Node","child_node:Node","legible_unique_name"),&Node::add_child_below_node,DEFVAL(false));

scene/main/node.h

@@ -313,6 +313,8 @@ public:
 	NodePath get_import_path() const;
 #endif
 
+	bool is_owned_by_parent() const;
+
 	void get_argument_options(const StringName& p_function,int p_idx,List<String>*r_options) const;
 
 	void clear_internal_tree_resource_paths();

tools/editor/scene_tree_dock.cpp

@@ -1388,6 +1388,13 @@ void SceneTreeDock::_create() {
 		}
 
 		String newname=n->get_name();
+
+		List<Node*> to_erase;
+		for(int i=0;i<n->get_child_count();i++) {
+			if (n->get_child(i)->get_owner()==NULL && n->is_owned_by_parent()) {
+				to_erase.push_back(n->get_child(i));
+			}
+		}
 		n->replace_by(newnode,true);
 
 		if (n==edited_scene) {
@@ -1408,6 +1415,11 @@ void SceneTreeDock::_create() {
 
 		memdelete(n);
 
+		while(to_erase.front()) {
+			memdelete(to_erase.front()->get());
+			to_erase.pop_front();
+		}
+
 
 
 	}