QmlDesigner: Clear errors when starting the puppet

Change-Id: I25d163ae48d094d6e7ba5059f7832d1b48ffec65
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>

src/plugins/qmldesigner/designercore/include/nodeinstanceview.h

@@ -170,6 +170,8 @@ private: // functions
 
     NodeInstance loadNode(const ModelNode &node);
 
+    void clearErrors();
+
     void removeAllInstanceNodeRelationships();
 
     void removeRecursiveChildRelationship(const ModelNode &removedNode);

src/plugins/qmldesigner/designercore/instances/nodeinstanceview.cpp

@@ -326,10 +326,17 @@ void NodeInstanceView::endPuppetTransaction()
     }
 }
 
+
+void NodeInstanceView::clearErrors()
+{
+    for (NodeInstance &instance : instances()) {
+        instance.setError({});
+    }
+}
+
 void NodeInstanceView::restartProcess()
 {
-    if (rootNodeInstance().isValid())
-        rootNodeInstance().setError({});
+    clearErrors();
     emitInstanceErrorChange({});
     emitDocumentMessage({}, {});
 
@@ -958,6 +965,8 @@ CreateSceneCommand NodeInstanceView::createCreateSceneCommand()
         }
     }
 
+    clearErrors();
+
     nodeList = filterNodesForSkipItems(nodeList);
 
     QList<VariantProperty> variantPropertyList;