diff --git a/src/core/hint.cpp b/src/core/hint.cpp
index c83947c..691a11e 100644
--- a/src/core/hint.cpp
+++ b/src/core/hint.cpp
@@ -55,13 +55,13 @@ bool Hint::contains(const QString &key) const
     return m_data.contains(key.toLower());
 }
 
-void Hint::setPrivateValue(const void *owner, const QString &key, const QVariant &value)
+void Hint::setPrivateValue(const void *owner, const QString &key, const QVariant &value) const
 {
     QPair<quintptr,QString> pk((quintptr)owner,key.toLower());
     m_privateData.insert(pk, value);
 }
 
-void Hint::setPrivateValue(const void *owner, const QString &key, QObject *value)
+void Hint::setPrivateValue(const void *owner, const QString &key, QObject *value) const
 {
     QPair<quintptr,QString> pk((quintptr)owner,key.toLower());
     m_privateData.insert(pk, qVariantFromValue(value));
diff --git a/src/core/hint.h b/src/core/hint.h
index d3872e8..101ad0d 100644
--- a/src/core/hint.h
+++ b/src/core/hint.h
@@ -79,7 +79,7 @@ public:
      * @param key the key
      * @param value the value
      */
-    void setPrivateValue(const void *owner, const QString &key, const QVariant &value);
+    void setPrivateValue(const void *owner, const QString &key, const QVariant &value) const;
 
     /**
      * Sets the value for the key depending on the owner
@@ -87,7 +87,7 @@ public:
      * @param key the key
      * @param value the value
      */
-    void setPrivateValue(const void *owner, const QString &key, QObject *value);
+    void setPrivateValue(const void *owner, const QString &key, QObject *value) const;
 
     /**
      * The associated value of the key if present, returns the default value otherwise.
@@ -110,7 +110,7 @@ private slots:
 
 private:
     QVariantHash m_data;
-    QHash<QPair<quintptr,QString>, QVariant> m_privateData;
+    mutable QHash<QPair<quintptr,QString>, QVariant> m_privateData;
 
     friend SNORE_EXPORT QDebug (::operator<<) ( QDebug, const Snore::Hint &);