Don't store the ID within a property. Since the ID is created automatically

and cannot be changed afterwards it should be stored as a field of the private
implementation.

Libs/XNAT/Core/ctkXnatObject.cpp

@@ -68,13 +68,15 @@ ctkXnatObject::~ctkXnatObject()
 //----------------------------------------------------------------------------
 QString ctkXnatObject::id() const
 {
-  return property(ctkXnatObjectFields::ID);
+  Q_D(const ctkXnatObject);
+  return d->id;
 }
 
 //----------------------------------------------------------------------------
 void ctkXnatObject::setId(const QString& id)
 {
-  setProperty(ctkXnatObjectFields::ID, id);
+  Q_D(ctkXnatObject);
+  d->id = id;
 }
 
 //----------------------------------------------------------------------------

Libs/XNAT/Core/ctkXnatObjectPrivate.h

@@ -49,6 +49,7 @@ private:
 
   QList<ctkXnatObject*> children;
 
+  QString id;
   QString description;
 
   QDateTime lastModifiedTime;