+ virtual QWidget * asQWidget() = 0;
+ virtual QWidget const * asQWidget() const = 0;
+
+ /// Session key.
+ /**
+ * This key must be used for any session setting.
+ **/
+ QString sessionKey() const;
+
+ /// Save session settings.
+ /**
+ * This default implementation saves the geometry state.
+ * Reimplement to save more settings.
+ **/
+ virtual void saveSession() const;
+
+ /// Restore session settings.
+ /**
+ * This default implementation restores the geometry state.
+ * Reimplement to restore more settings.
+ **/
+ virtual void restoreSession();
+