prohibit double-creation of parameterContainer

GUI/Model/Job/ParameterTreeUtils.cpp

@@ -90,7 +90,9 @@ void populateParameterContainer(SessionItem* container, const SessionItem* sourc
 
 void GUI::Model::ParameterTreeUtils::createParameterTree(JobItem* jobItem)
 {
-    auto* container = jobItem->createParameterContainerItem();
+    auto* container = jobItem->parameterContainerItem();
+    if (!container)
+        container = jobItem->createParameterContainerItem();
 
     populateParameterContainer(container, jobItem->materialContainerItem());