diff --git a/GUI/Model/Mask/MaskCatalog.h b/GUI/Model/Mask/MaskCatalog.h
index 05eb73bef71c201a95bfa067b1739fd46648754c..d18e8e0eaefef9866a4c42e436220104816e4f0b 100644
--- a/GUI/Model/Mask/MaskCatalog.h
+++ b/GUI/Model/Mask/MaskCatalog.h
@@ -22,8 +22,6 @@ class MaskItem;
 
 class MaskCatalog {
 public:
-    using BaseItem = MaskItem;
-
     // Do not change the numbering! It is serialized!
     enum class Type : uint8_t {
         RegionOfInterest = 0,
diff --git a/GUI/Model/Sample/ParticleCatalog.h b/GUI/Model/Sample/ParticleCatalog.h
index ce75f98406e57cf10275e8e4795bba0a89106aa3..860c73a3e9c7031f919c20d484b75c9bd20b68b5 100644
--- a/GUI/Model/Sample/ParticleCatalog.h
+++ b/GUI/Model/Sample/ParticleCatalog.h
@@ -23,8 +23,6 @@ class MaterialsSet;
 
 class ParticleCatalog {
 public:
-    using BaseItem = ItemWithParticles;
-
     // Do not change the numbering! It is serialized!
     enum class Type : uint8_t { Particle = 1, Composition = 2, CoreShell = 3, Mesocrystal = 4 };
 
diff --git a/GUI/Model/Sim/InstrumentCatalog.h b/GUI/Model/Sim/InstrumentCatalog.h
index f82ef88e0ee3b3e832b62c06f6f4ff3167657e47..61c8c5061ef3f81474501460fc957608f805e61c 100644
--- a/GUI/Model/Sim/InstrumentCatalog.h
+++ b/GUI/Model/Sim/InstrumentCatalog.h
@@ -22,8 +22,6 @@ class InstrumentItem;
 
 class InstrumentCatalog {
 public:
-    using BaseItem = InstrumentItem;
-
     // Do not change the numbering! It is serialized!
     enum class Type : uint8_t { Scatter2D = 0, Offspec = 1, Specular = 2, Depthprobe = 3 };