Index: sources/gui/qml/pages/pretreatment/PreTreatmentBase.qml
===================================================================
diff -u -r1286d74bd015276aab604808be2766136091c125 -r7fb13d9e1a453a37ab4dea5536e0f19ed6e272d2
--- sources/gui/qml/pages/pretreatment/PreTreatmentBase.qml	(.../PreTreatmentBase.qml)	(revision 1286d74bd015276aab604808be2766136091c125)
+++ sources/gui/qml/pages/pretreatment/PreTreatmentBase.qml	(.../PreTreatmentBase.qml)	(revision 7fb13d9e1a453a37ab4dea5536e0f19ed6e272d2)
@@ -34,11 +34,9 @@
 
     // update model for instruction based steps
     function updateModel () {
-        let  stepName = stepNames[stackStepIndex]
-        if ( stepName === undefined ) stepName = ""
+        let stepName = stepNames[stackStepIndex] ?? ""
+        let group    = vSettings.groupFormat(stepName, vSettings.advancedMode || _root.subStepName.length === 0 ? "" : _root.subStepName )
 
-        let group = vSettings.groupFormat(stepName, vSettings.advancedMode || _root.subStepName.length === 0 ? "" : _root.subStepName )
-
         let instructionsGroup    = vSettings.instructions[group]
 
         if ( instructionsGroup !== undefined ) {