diff --git a/GUI/Model/Sample/FTDecayFunctionItemCatalogs.cpp b/GUI/Model/Sample/FTDecayFunctionItemCatalogs.cpp
index 1fcc568bb9f04eb7d87bfbeaf4fcc90fcb82868a..87680103e49dbbdfaec5444cb5ff14f0084c1fda 100644
--- a/GUI/Model/Sample/FTDecayFunctionItemCatalogs.cpp
+++ b/GUI/Model/Sample/FTDecayFunctionItemCatalogs.cpp
@@ -60,12 +60,12 @@ FTDecayFunction1DItemCatalog::UiInfo FTDecayFunction1DItemCatalog::uiInfo(Type t
     }
 }
 
-FTDecayFunction1DItemCatalog::Type FTDecayFunction1DItemCatalog::type(CatalogedType* item)
+FTDecayFunction1DItemCatalog::Type FTDecayFunction1DItemCatalog::type(const CatalogedType* item)
 {
     ASSERT(item);
 
 #define CHECK(type)                                                                                \
-    if (dynamic_cast<FTDecayFunction1D##type##Item*>(item))                                        \
+    if (dynamic_cast<const FTDecayFunction1D##type##Item*>(item))                                  \
     return Type::type
 
     CHECK(Cauchy);
diff --git a/GUI/Model/Sample/FTDecayFunctionItemCatalogs.h b/GUI/Model/Sample/FTDecayFunctionItemCatalogs.h
index 06676c9b1984b4141e489b61869bb744d120f803..295de4e3ec282add51e3a8b6f907044a2c148dc0 100644
--- a/GUI/Model/Sample/FTDecayFunctionItemCatalogs.h
+++ b/GUI/Model/Sample/FTDecayFunctionItemCatalogs.h
@@ -44,7 +44,7 @@ public:
     static UiInfo uiInfo(Type t);
 
     //! Returns the enum type of the given item.
-    static Type type(CatalogedType* item);
+    static Type type(const CatalogedType* item);
 };
 
 class FTDecayFunction2DItemCatalog {
diff --git a/GUI/Model/Sample/FTDistributionItemCatalogs.cpp b/GUI/Model/Sample/FTDistributionItemCatalogs.cpp
index 6c483215be5823b3acb461f5057068039e7c5d87..4f283763d14463612a29856c950ba91b0e95ce52 100644
--- a/GUI/Model/Sample/FTDistributionItemCatalogs.cpp
+++ b/GUI/Model/Sample/FTDistributionItemCatalogs.cpp
@@ -68,12 +68,12 @@ FTDistribution1DItemCatalog::UiInfo FTDistribution1DItemCatalog::uiInfo(Type typ
     }
 }
 
-FTDistribution1DItemCatalog::Type FTDistribution1DItemCatalog::type(CatalogedType* item)
+FTDistribution1DItemCatalog::Type FTDistribution1DItemCatalog::type(const CatalogedType* item)
 {
     ASSERT(item);
 
 #define CHECK(type)                                                                                \
-    if (dynamic_cast<FTDistribution1D##type##Item*>(item))                                         \
+    if (dynamic_cast<const FTDistribution1D##type##Item*>(item))                                   \
     return Type::type
 
     CHECK(Cauchy);
diff --git a/GUI/Model/Sample/FTDistributionItemCatalogs.h b/GUI/Model/Sample/FTDistributionItemCatalogs.h
index 6b4b0f9820474cc42509fb82c973bfc3f622ee36..aa274f21712328010dde0aa8fe017fd32bc08e2a 100644
--- a/GUI/Model/Sample/FTDistributionItemCatalogs.h
+++ b/GUI/Model/Sample/FTDistributionItemCatalogs.h
@@ -51,7 +51,7 @@ public:
     static UiInfo uiInfo(Type t);
 
     //! Returns the enum type of the given item.
-    static Type type(CatalogedType* item);
+    static Type type(const CatalogedType* item);
 };
 
 class FTDistribution2DItemCatalog {
diff --git a/GUI/Model/Sample/InterferenceItems.cpp b/GUI/Model/Sample/InterferenceItems.cpp
index 48909fb543449beefbeb41af5477b69b35530f7a..d132bc4c814a4d8ee58f45317e1e32eb99c2a9df 100644
--- a/GUI/Model/Sample/InterferenceItems.cpp
+++ b/GUI/Model/Sample/InterferenceItems.cpp
@@ -291,7 +291,7 @@ void InterferenceFinite2DLatticeItem::serialize(Serializer& s)
     s.rw(m_domainSize2);
 }
 
-UIntDescriptor InterferenceFinite2DLatticeItem::domainSize1()
+UIntDescriptor InterferenceFinite2DLatticeItem::domainSize1() const
 {
     return m_domainSize1;
 }
@@ -301,7 +301,7 @@ void InterferenceFinite2DLatticeItem::setDomainSize1(const unsigned int size)
     m_domainSize1.set(size);
 }
 
-UIntDescriptor InterferenceFinite2DLatticeItem::domainSize2()
+UIntDescriptor InterferenceFinite2DLatticeItem::domainSize2() const
 {
     return m_domainSize2;
 }
diff --git a/GUI/Model/Sample/InterferenceItems.h b/GUI/Model/Sample/InterferenceItems.h
index 4c0496440a44b1cf91d369afa094b47a88930611..e86c2157db0695db3d678520bce8e69250f2cefa 100644
--- a/GUI/Model/Sample/InterferenceItems.h
+++ b/GUI/Model/Sample/InterferenceItems.h
@@ -131,9 +131,9 @@ public:
     std::unique_ptr<IInterference> createInterference() const override;
     void serialize(Serializer& s) override;
 
-    UIntDescriptor domainSize1();
+    UIntDescriptor domainSize1() const;
     void setDomainSize1(unsigned int domain_size1);
-    UIntDescriptor domainSize2();
+    UIntDescriptor domainSize2() const;
     void setDomainSize2(unsigned int domain_size2);
 
 private:
diff --git a/GUI/Model/Sample/MesoCrystalItem.cpp b/GUI/Model/Sample/MesoCrystalItem.cpp
index 200ab4b6e8aaa1e8b9c06574c5f8f681b7a786cc..feecb787e047e7da8fbe4f8167c06c7a7192908f 100644
--- a/GUI/Model/Sample/MesoCrystalItem.cpp
+++ b/GUI/Model/Sample/MesoCrystalItem.cpp
@@ -114,7 +114,7 @@ std::unique_ptr<IBornFF> MesoCrystalItem::getOuterShape() const
     return m_outerShape->createFormFactor();
 }
 
-SelectionDescriptor<FormFactorItem*> MesoCrystalItem::outerShape()
+SelectionDescriptor<FormFactorItem*> MesoCrystalItem::outerShape() const
 {
     return m_outerShape;
 }
diff --git a/GUI/Model/Sample/MesoCrystalItem.h b/GUI/Model/Sample/MesoCrystalItem.h
index 9e1c89f22bcf71583fb9d716a91f0f7de7a7292f..0e9fd0746ba31d64478ffc68c74f31aba0444ee6 100644
--- a/GUI/Model/Sample/MesoCrystalItem.h
+++ b/GUI/Model/Sample/MesoCrystalItem.h
@@ -39,7 +39,7 @@ public:
     std::unique_ptr<IBornFF> getOuterShape() const;
     template <typename T> T* setOuterShapeType();
 
-    SelectionDescriptor<FormFactorItem*> outerShape();
+    SelectionDescriptor<FormFactorItem*> outerShape() const;
     void setOuterShape(FormFactorItem* p);
 
     ItemWithParticles* basisParticle() const;