diff --git a/GUI/View/SampleDesigner/MaterialInplaceForm.cpp b/GUI/View/SampleDesigner/MaterialInplaceForm.cpp
index c3e055c43b9df65eb68c03bd96d24375d6c74799..2fec2dfcb77cfad8eb865817d87848e67f975b9a 100644
--- a/GUI/View/SampleDesigner/MaterialInplaceForm.cpp
+++ b/GUI/View/SampleDesigner/MaterialInplaceForm.cpp
@@ -24,6 +24,7 @@
 #include "GUI/View/Numeric/DoubleSpinBox.h"
 #include "GUI/View/SampleDesigner/LayerEditorUtils.h"
 #include "GUI/View/SampleDesigner/SampleEditorController.h"
+#include "GUI/View/SampleDesigner/SampleForm.h"
 #include "GUI/View/Tool/Globals.h"
 #include "GUI/View/Tool/LayoutUtils.h"
 #include <QGridLayout>
@@ -74,6 +75,7 @@ void MaterialInplaceForm::selectMaterial()
         createWidgets();
         connect(itemWithMaterial()->materialItem(), &MaterialItem::dataChanged, this,
                 &MaterialInplaceForm::onMaterialChanged);
+        m_ec->sampleForm()->updateUnits(); // necessary on switch from refractive index to SLD
     } else {
         updateValues(); // necessary, since in the material editor the values could have been
                         // changed without selecting a different material