diff --git a/src/plugins/qmldesigner/designercore/include/modelnode.h b/src/plugins/qmldesigner/designercore/include/modelnode.h
index 958af72ef1c..d0be096ceff 100644
--- a/src/plugins/qmldesigner/designercore/include/modelnode.h
+++ b/src/plugins/qmldesigner/designercore/include/modelnode.h
@@ -165,7 +165,7 @@ public:
     QVariant toVariant() const;
 
     QVariant auxiliaryData(const QString &name) const;
-    void setAuxiliaryData(const QString &name, const QVariant &data);
+    void setAuxiliaryData(const QString &name, const QVariant &data) const;
     bool hasAuxiliaryData(const QString &name) const;
 
     qint32 internalId() const;
diff --git a/src/plugins/qmldesigner/designercore/model/modelnode.cpp b/src/plugins/qmldesigner/designercore/model/modelnode.cpp
index cf73565acc1..ac8927f76e2 100644
--- a/src/plugins/qmldesigner/designercore/model/modelnode.cpp
+++ b/src/plugins/qmldesigner/designercore/model/modelnode.cpp
@@ -902,7 +902,7 @@ QVariant ModelNode::auxiliaryData(const QString &name) const
     return internalNode()->auxiliaryData(name);
 }
 
-void ModelNode::setAuxiliaryData(const QString &name, const QVariant &data)
+void ModelNode::setAuxiliaryData(const QString &name, const QVariant &data) const
 {
     Internal::WriteLocker locker(m_model.data());
     m_model.data()->m_d->setAuxiliaryData(internalNode(), name, data);