diff --git a/FDTD/operator_cylinder.cpp b/FDTD/operator_cylinder.cpp
index 0b5eefd..87f7c60 100644
--- a/FDTD/operator_cylinder.cpp
+++ b/FDTD/operator_cylinder.cpp
@@ -307,7 +307,10 @@ void Operator_Cylinder::ApplyMagneticBC(bool* dirs)
 void Operator_Cylinder::AddExtension(Operator_Extension* op_ext)
 {
 	if (op_ext->IsCylinderCoordsSave(CC_closedAlpha, CC_R0_included))
-		m_Op_exts.push_back(op_ext);
+		Operator_Multithread::AddExtension(op_ext);
 	else
+	{
+		delete op_ext;
 		cerr << "Operator_Cylinder::AddExtension: Warning: Operator extension \"" << op_ext->GetExtensionName() << "\" is not compatible with cylinder-coords!! skipping...!" << endl;
+	}
 }
diff --git a/FDTD/operator_cylindermultigrid.cpp b/FDTD/operator_cylindermultigrid.cpp
index 2758e66..f4f92c5 100644
--- a/FDTD/operator_cylindermultigrid.cpp
+++ b/FDTD/operator_cylindermultigrid.cpp
@@ -498,6 +498,7 @@ void Operator_CylinderMultiGrid::AddExtension(Operator_Extension* op_ext)
 	//check whether extension is save to use in multi-grid
 	if (op_ext->IsCylindricalMultiGridSave(false)==false)
 	{
+		delete op_ext;
 		cerr << "Operator_CylinderMultiGrid::AddExtension: Warning: Operator extension \"" << op_ext->GetExtensionName() << "\" is not compatible with cylindrical multi-grids!! skipping...!" << endl;
 		return;
 	}