diff --git a/libsrc/general/optmem.cpp b/libsrc/general/optmem.cpp
index 4d31f987..2fba3043 100644
--- a/libsrc/general/optmem.cpp
+++ b/libsrc/general/optmem.cpp
@@ -27,8 +27,10 @@ namespace netgen
 
   BlockAllocator :: ~BlockAllocator ()
   {
+    // cout << "****************** delete BlockAllocator " << endl;
     for (int i = 0; i < bablocks.Size(); i++)
       delete [] bablocks[i];
+    bablocks.SetSize(0);
   }
 
   void * BlockAllocator :: Alloc ()
diff --git a/libsrc/general/optmem.hpp b/libsrc/general/optmem.hpp
index cd55f16e..aaa02dd4 100644
--- a/libsrc/general/optmem.hpp
+++ b/libsrc/general/optmem.hpp
@@ -48,6 +48,7 @@ public:
   ///
   void Free (void * p)
   {
+    if (!bablocks.Size()) return;
     *(void**)p = freelist;
     freelist = p;
   }
diff --git a/libsrc/include/nginterface_v2.hpp b/libsrc/include/nginterface_v2.hpp
index 8ddedc71..0317022f 100644
--- a/libsrc/include/nginterface_v2.hpp
+++ b/libsrc/include/nginterface_v2.hpp
@@ -167,6 +167,7 @@ namespace netgen
 
     void LoadMesh (istream & str);
     void SaveMesh (ostream & str) const;
+    void UpdateTopology ();
     void DoArchive (ngstd::Archive & archive);
 
     virtual ~Ngx_Mesh();
diff --git a/libsrc/interface/nginterface_v2.cpp b/libsrc/interface/nginterface_v2.cpp
index a46acdf2..8b387131 100644
--- a/libsrc/interface/nginterface_v2.cpp
+++ b/libsrc/interface/nginterface_v2.cpp
@@ -6,6 +6,7 @@
 
 #include "nginterface.h"
 #include "nginterface_v2.hpp"
+#include <visual.hpp>
 
 namespace netgen
 {
@@ -22,7 +23,11 @@ namespace netgen
   shared_ptr<Mesh> Ngx_Mesh :: SelectMesh () const
   {
     shared_ptr<Mesh> hmesh = netgen::mesh;
+
     netgen::mesh = mesh;
+    vssolution.SetMesh(mesh);
+    vsmesh.SetMesh(mesh);
+
     return hmesh;
   }
   
@@ -80,6 +85,11 @@ namespace netgen
       }
   }
 
+  void Ngx_Mesh :: UpdateTopology ()
+  {
+    if (mesh)
+      mesh -> UpdateTopology();
+  }
 
 
   /*
diff --git a/libsrc/meshing/meshclass.cpp b/libsrc/meshing/meshclass.cpp
index 031283b5..a6d62e65 100644
--- a/libsrc/meshing/meshclass.cpp
+++ b/libsrc/meshing/meshclass.cpp
@@ -47,6 +47,7 @@ namespace netgen
 
   Mesh :: ~Mesh()
   {
+    // cout << "******************** deleting Mesh **********" << endl;
     delete lochfunc;
     delete boundaryedges;
     delete surfelementht;