diff --git a/src/Editor/Undo/CCreateInstanceCommand.cpp b/src/Editor/Undo/CCreateInstanceCommand.cpp
index bc4e1d88..557b0f14 100644
--- a/src/Editor/Undo/CCreateInstanceCommand.cpp
+++ b/src/Editor/Undo/CCreateInstanceCommand.cpp
@@ -12,7 +12,7 @@ CCreateInstanceCommand::CCreateInstanceCommand(CWorldEditor *pEditor, CScriptTem
     , mpNewInstance(nullptr)
     , mpNewNode(nullptr)
 {
-    ASSERT(mLayerIndex != -1);
+    ASSERT(mLayerIndex != UINT32_MAX);
 }
 
 void CCreateInstanceCommand::undo()
diff --git a/src/Editor/Undo/CCreateInstanceCommand.h b/src/Editor/Undo/CCreateInstanceCommand.h
index 50dd0728..49f7797b 100644
--- a/src/Editor/Undo/CCreateInstanceCommand.h
+++ b/src/Editor/Undo/CCreateInstanceCommand.h
@@ -24,9 +24,9 @@ class CCreateInstanceCommand : public IUndoCommand
 
 public:
     CCreateInstanceCommand(CWorldEditor *pEditor, CScriptTemplate *pTemplate, CScriptLayer *pLayer, const CVector3f& rkPosition);
-    void undo();
-    void redo();
-    bool AffectsCleanState() const { return true; }
+    void undo() override;
+    void redo() override;
+    bool AffectsCleanState() const override { return true; }
 };
 
 #endif // CCREATEINSTANCECOMMAND_H