diff --git a/FDTD/engine_extension.cpp b/FDTD/engine_extension.cpp
index ec4b2b9..e185b65 100644
--- a/FDTD/engine_extension.cpp
+++ b/FDTD/engine_extension.cpp
@@ -24,3 +24,7 @@ Engine_Extension::Engine_Extension(Operator_Extension* op_ext)
 	m_Op_ext = op_ext;
 	m_Eng = NULL;
 }
+
+Engine_Extension::~Engine_Extension()
+{
+}
diff --git a/FDTD/engine_extension.h b/FDTD/engine_extension.h
index 8bbf830..bf73aa1 100644
--- a/FDTD/engine_extension.h
+++ b/FDTD/engine_extension.h
@@ -25,6 +25,8 @@ class Engine;
 class Engine_Extension
 {
 public:
+	virtual ~Engine_Extension();
+
 	//! This methode will be called __before__ the main engine does the usual voltage updates. This methode may __not__ change the engine voltages!!!
 	virtual void DoPreVoltageUpdates() {}
 	//! This methode will be called __after__ the main engine does the usual voltage updates. This methode may __not__ change the engine voltages!!!