diff --git a/src/OBJECT/SMESH_Actor.cxx b/src/OBJECT/SMESH_Actor.cxx
index 34c956b5c..f7f6a807c 100644
--- a/src/OBJECT/SMESH_Actor.cxx
+++ b/src/OBJECT/SMESH_Actor.cxx
@@ -26,23 +26,23 @@
 //  Module : SMESH
 
 #include "SMESH_ActorDef.h"
+
+#include "SMDS_UnstructuredGrid.hxx"
 #include "SMESH_ActorUtils.h"
+#include "SMESH_CellLabelActor.h"
+#include "SMESH_ControlsDef.hxx"
 #include "SMESH_DeviceActor.h"
 #include "SMESH_NodeLabelActor.h"
-#include "SMESH_CellLabelActor.h"
 #include "SMESH_ObjectDef.h"
-#include "SMESH_ControlsDef.hxx"
-#include "SMDS_UnstructuredGrid.hxx"
-#include "SMESH_ScalarBarActor.h"
-#include "VTKViewer_ExtractUnstructuredGrid.h"
-#include "VTKViewer_FramedTextActor.h"
-#include "SALOME_InteractiveObject.hxx"
 #include "SMESH_SVTKActor.h"
-
-#include "SUIT_Session.h"
-#include "SUIT_ResourceMgr.h"
+#include "SMESH_ScalarBarActor.h"
 
 #include <Qtx.h>
+#include <SALOME_InteractiveObject.hxx>
+#include <SUIT_ResourceMgr.h>
+#include <SUIT_Session.h>
+#include <VTKViewer_ExtractUnstructuredGrid.h>
+#include <VTKViewer_FramedTextActor.h>
 
 #ifndef DISABLE_PLOT2DVIEWER
 #include <SPlot2d_Histogram.h>
@@ -117,6 +117,9 @@ SMESH_Actor* SMESH_Actor::New(TVisualObjPtr theVisualObj,
 SMESH_ActorDef::SMESH_ActorDef()
 {
   if(MYDEBUG) MESSAGE("SMESH_ActorDef - "<<this);
+
+  SALOME_Actor::SetVisibility(false); // avoid update of pipelines
+
   myBaseActor = SMESH_DeviceActor::New();
 
   myTimeStamp = vtkTimeStamp::New();
@@ -1134,6 +1137,13 @@ int SMESH_ActorDef::GetNumberControlEntities()
 
 void SMESH_ActorDef::AddToRender(vtkRenderer* theRenderer)
 {
+  if ( !mySelector || !mySelector->IsSelectionEnabled() )
+  {
+    myBaseActor->SetUnstructuredGrid( NULL );
+    myHighlitableActor->SetUnstructuredGrid( NULL );
+    // theRenderer->AddActor(this);
+    // cout << "SMESH_ActorDef " << this << endl;
+  }
   theRenderer->AddActor(myBaseActor);
   theRenderer->AddActor(myNodeExtActor);
   theRenderer->AddActor(my1DExtActor);
@@ -1274,7 +1284,9 @@ bool SMESH_ActorDef::Init(TVisualObjPtr theVisualObj,
 
 double* SMESH_ActorDef::GetBounds()
 {
-  return myNodeActor->GetBounds();
+  if ( GetNumberOfClippingPlanes() + myPlaneCollection->GetNumberOfItems() > 0 )
+    return myNodeActor->GetBounds();
+  return myVisualObj->GetUnstructuredGrid()->GetPoints()->GetBounds();
 }
 
 
@@ -1603,97 +1615,108 @@ void SMESH_ActorDef::SetEntityMode(unsigned int theMode)
   myBaseActor->myGeomFilter->SetInside(myEntityMode != myEntityState);
 
   myEntityMode = theMode;
-  VTKViewer_ExtractUnstructuredGrid* aFilter = NULL;
-  aFilter = myBaseActor->GetExtractUnstructuredGrid();
-  aFilter->ClearRegisteredCellsWithType();
-  aFilter->SetModeOfChanging(VTKViewer_ExtractUnstructuredGrid::eAdding);
 
+  VTKViewer_ExtractUnstructuredGrid* aFilter = myBaseActor->GetExtractUnstructuredGrid();
+  aFilter->ClearRegisteredCellsWithType();
   VTKViewer_ExtractUnstructuredGrid* aHightFilter = myHighlitableActor->GetExtractUnstructuredGrid();
   aHightFilter->ClearRegisteredCellsWithType();
-  aHightFilter->SetModeOfChanging(VTKViewer_ExtractUnstructuredGrid::eAdding);
 
-  if (myEntityMode & e0DElements) {
-    if (MYDEBUG) MESSAGE("0D ELEMENTS");
-    aFilter->RegisterCellsWithType(VTK_VERTEX);
-    aHightFilter->RegisterCellsWithType(VTK_VERTEX);
+  bool isPassAll =
+    (( myEntityMode & e0DElements || myVisualObj->GetNbEntities(SMDSAbs_0DElement) == 0 ) &&
+     ( myEntityMode & eBallElem   || myVisualObj->GetNbEntities(SMDSAbs_Ball)      == 0 ) &&
+     ( myEntityMode & eEdges      || myVisualObj->GetNbEntities(SMDSAbs_Edge)      == 0 ) &&
+     ( myEntityMode & eFaces      || myVisualObj->GetNbEntities(SMDSAbs_Face)      == 0 ) &&
+     ( myEntityMode & eVolumes    || myVisualObj->GetNbEntities(SMDSAbs_Volume)    == 0 ));
+  if ( isPassAll && myEntityMode )
+  {
+    aFilter->SetModeOfChanging(VTKViewer_ExtractUnstructuredGrid::ePassAll);
+    aHightFilter->SetModeOfChanging(VTKViewer_ExtractUnstructuredGrid::ePassAll);
   }
+  else
+  {
+    aFilter->SetModeOfChanging(VTKViewer_ExtractUnstructuredGrid::eAdding);
+    aHightFilter->SetModeOfChanging(VTKViewer_ExtractUnstructuredGrid::eAdding);
 
-  if (myEntityMode & eBallElem) {
-    aFilter->RegisterCellsWithType(VTK_POLY_VERTEX);
+    if (myEntityMode & e0DElements) {
+      aFilter->RegisterCellsWithType(VTK_VERTEX);
+      aHightFilter->RegisterCellsWithType(VTK_VERTEX);
+    }
+
+    if (myEntityMode & eBallElem) {
+      aFilter->RegisterCellsWithType(VTK_POLY_VERTEX);
+    }
+
+    if (myEntityMode & eEdges) {
+      aFilter->RegisterCellsWithType(VTK_LINE);
+      aFilter->RegisterCellsWithType(VTK_QUADRATIC_EDGE);
+
+      aHightFilter->RegisterCellsWithType(VTK_LINE);
+      aHightFilter->RegisterCellsWithType(VTK_QUADRATIC_EDGE);
+    }
+
+    if (myEntityMode & eFaces) {
+      aFilter->RegisterCellsWithType(VTK_TRIANGLE);
+      aFilter->RegisterCellsWithType(VTK_QUAD);
+      aFilter->RegisterCellsWithType(VTK_POLYGON);
+      aFilter->RegisterCellsWithType(VTK_QUADRATIC_TRIANGLE);
+      aFilter->RegisterCellsWithType(VTK_QUADRATIC_QUAD);
+      aFilter->RegisterCellsWithType(VTK_QUADRATIC_POLYGON);
+      aFilter->RegisterCellsWithType(VTK_BIQUADRATIC_QUAD);
+      aFilter->RegisterCellsWithType(VTK_BIQUADRATIC_TRIANGLE);
+
+      aHightFilter->RegisterCellsWithType(VTK_TRIANGLE);
+      aHightFilter->RegisterCellsWithType(VTK_QUAD);
+      aHightFilter->RegisterCellsWithType(VTK_POLYGON);
+      aHightFilter->RegisterCellsWithType(VTK_QUADRATIC_TRIANGLE);
+      aHightFilter->RegisterCellsWithType(VTK_QUADRATIC_QUAD);
+      aHightFilter->RegisterCellsWithType(VTK_QUADRATIC_POLYGON);
+      aHightFilter->RegisterCellsWithType(VTK_BIQUADRATIC_QUAD);
+      aHightFilter->RegisterCellsWithType(VTK_BIQUADRATIC_TRIANGLE);
+    }
+
+    if (myEntityMode & eVolumes) {
+      aFilter->RegisterCellsWithType(VTK_TETRA);
+      aFilter->RegisterCellsWithType(VTK_VOXEL);
+      aFilter->RegisterCellsWithType(VTK_HEXAHEDRON);
+      aFilter->RegisterCellsWithType(VTK_WEDGE);
+      aFilter->RegisterCellsWithType(VTK_PYRAMID);
+      aFilter->RegisterCellsWithType(VTK_HEXAGONAL_PRISM);
+      aFilter->RegisterCellsWithType(VTK_QUADRATIC_TETRA);
+      aFilter->RegisterCellsWithType(VTK_QUADRATIC_HEXAHEDRON);
+      aFilter->RegisterCellsWithType(VTK_TRIQUADRATIC_HEXAHEDRON);
+      aFilter->RegisterCellsWithType(VTK_QUADRATIC_PYRAMID);
+      aFilter->RegisterCellsWithType(VTK_QUADRATIC_WEDGE);
+      aFilter->RegisterCellsWithType(VTK_CONVEX_POINT_SET);
+      aFilter->RegisterCellsWithType(VTK_POLYHEDRON);
+
+      aHightFilter->RegisterCellsWithType(VTK_TETRA);
+      aHightFilter->RegisterCellsWithType(VTK_VOXEL);
+      aHightFilter->RegisterCellsWithType(VTK_HEXAHEDRON);
+      aHightFilter->RegisterCellsWithType(VTK_WEDGE);
+      aHightFilter->RegisterCellsWithType(VTK_PYRAMID);
+      aHightFilter->RegisterCellsWithType(VTK_HEXAGONAL_PRISM);
+      aHightFilter->RegisterCellsWithType(VTK_QUADRATIC_TETRA);
+      aHightFilter->RegisterCellsWithType(VTK_QUADRATIC_HEXAHEDRON);
+      aHightFilter->RegisterCellsWithType(VTK_TRIQUADRATIC_HEXAHEDRON);
+      aHightFilter->RegisterCellsWithType(VTK_QUADRATIC_WEDGE);
+      aHightFilter->RegisterCellsWithType(VTK_QUADRATIC_PYRAMID);
+      aHightFilter->RegisterCellsWithType(VTK_CONVEX_POINT_SET);
+      aHightFilter->RegisterCellsWithType(VTK_POLYHEDRON);
+    }
   }
-
-  if (myEntityMode & eEdges) {
-    if (MYDEBUG) MESSAGE("EDGES");
-    aFilter->RegisterCellsWithType(VTK_LINE);
-    aFilter->RegisterCellsWithType(VTK_QUADRATIC_EDGE);
-
-    aHightFilter->RegisterCellsWithType(VTK_LINE);
-    aHightFilter->RegisterCellsWithType(VTK_QUADRATIC_EDGE);
-  }
-
-  if (myEntityMode & eFaces) {
-    if (MYDEBUG) MESSAGE("FACES");
-    aFilter->RegisterCellsWithType(VTK_TRIANGLE);
-    aFilter->RegisterCellsWithType(VTK_QUAD);
-    aFilter->RegisterCellsWithType(VTK_POLYGON);
-    aFilter->RegisterCellsWithType(VTK_QUADRATIC_TRIANGLE);
-    aFilter->RegisterCellsWithType(VTK_QUADRATIC_QUAD);
-    aFilter->RegisterCellsWithType(VTK_QUADRATIC_POLYGON);
-    aFilter->RegisterCellsWithType(VTK_BIQUADRATIC_QUAD);
-    aFilter->RegisterCellsWithType(VTK_BIQUADRATIC_TRIANGLE);
-
-    aHightFilter->RegisterCellsWithType(VTK_TRIANGLE);
-    aHightFilter->RegisterCellsWithType(VTK_QUAD);
-    aHightFilter->RegisterCellsWithType(VTK_POLYGON);
-    aHightFilter->RegisterCellsWithType(VTK_QUADRATIC_TRIANGLE);
-    aHightFilter->RegisterCellsWithType(VTK_QUADRATIC_QUAD);
-    aHightFilter->RegisterCellsWithType(VTK_QUADRATIC_POLYGON);
-    aHightFilter->RegisterCellsWithType(VTK_BIQUADRATIC_QUAD);
-    aHightFilter->RegisterCellsWithType(VTK_BIQUADRATIC_TRIANGLE);
-  }
-
-  if (myEntityMode & eVolumes) {
-    if (MYDEBUG) MESSAGE("VOLUMES");
-    aFilter->RegisterCellsWithType(VTK_TETRA);
-    aFilter->RegisterCellsWithType(VTK_VOXEL);
-    aFilter->RegisterCellsWithType(VTK_HEXAHEDRON);
-    aFilter->RegisterCellsWithType(VTK_WEDGE);
-    aFilter->RegisterCellsWithType(VTK_PYRAMID);
-    aFilter->RegisterCellsWithType(VTK_HEXAGONAL_PRISM);
-    aFilter->RegisterCellsWithType(VTK_QUADRATIC_TETRA);
-    aFilter->RegisterCellsWithType(VTK_QUADRATIC_HEXAHEDRON);
-    aFilter->RegisterCellsWithType(VTK_TRIQUADRATIC_HEXAHEDRON);
-    aFilter->RegisterCellsWithType(VTK_QUADRATIC_PYRAMID);
-    aFilter->RegisterCellsWithType(VTK_QUADRATIC_WEDGE);
-    aFilter->RegisterCellsWithType(VTK_CONVEX_POINT_SET);
-    aFilter->RegisterCellsWithType(VTK_POLYHEDRON);
-
-    aHightFilter->RegisterCellsWithType(VTK_TETRA);
-    aHightFilter->RegisterCellsWithType(VTK_VOXEL);
-    aHightFilter->RegisterCellsWithType(VTK_HEXAHEDRON);
-    aHightFilter->RegisterCellsWithType(VTK_WEDGE);
-    aHightFilter->RegisterCellsWithType(VTK_PYRAMID);
-    aHightFilter->RegisterCellsWithType(VTK_HEXAGONAL_PRISM);
-    aHightFilter->RegisterCellsWithType(VTK_QUADRATIC_TETRA);
-    aHightFilter->RegisterCellsWithType(VTK_QUADRATIC_HEXAHEDRON);
-    aHightFilter->RegisterCellsWithType(VTK_TRIQUADRATIC_HEXAHEDRON);
-    aHightFilter->RegisterCellsWithType(VTK_QUADRATIC_WEDGE);
-    aHightFilter->RegisterCellsWithType(VTK_QUADRATIC_PYRAMID);
-    aHightFilter->RegisterCellsWithType(VTK_CONVEX_POINT_SET);
-    aHightFilter->RegisterCellsWithType(VTK_POLYHEDRON);
-  }
-  aFilter->Update();
+  if ( GetVisibility() )
+    aFilter->Update();
   if (MYDEBUG) MESSAGE(aFilter->GetOutput()->GetNumberOfCells());
   SetVisibility(GetVisibility(),false);
 }
 
 void SMESH_ActorDef::SetRepresentation (int theMode)
 {
-  int aNbEdges = myVisualObj->GetNbEntities(SMDSAbs_Edge);
-  int aNbFaces = myVisualObj->GetNbEntities(SMDSAbs_Face);
+  int aNbEdges   = myVisualObj->GetNbEntities(SMDSAbs_Edge);
+  int aNbFaces   = myVisualObj->GetNbEntities(SMDSAbs_Face);
   int aNbVolumes = myVisualObj->GetNbEntities(SMDSAbs_Volume);
-  int aNb0Ds       = myVisualObj->GetNbEntities(SMDSAbs_0DElement);
-  int aNbBalls       = myVisualObj->GetNbEntities(SMDSAbs_Ball);
+  int aNb0Ds     = myVisualObj->GetNbEntities(SMDSAbs_0DElement);
+  int aNbBalls   = myVisualObj->GetNbEntities(SMDSAbs_Ball);
 
   if (theMode < 0) {
     myRepresentation = eSurface;
@@ -1835,6 +1858,11 @@ void SMESH_ActorDef::UpdateHighlight()
   case SMESH_DeviceActor::eSurface:
   case SMESH_DeviceActor::eWireframe:
     {
+      // if ( !mySelector || !mySelector->IsSelectionEnabled() )
+      //   myHighlitableActor->SetUnstructuredGrid( NULL );
+      // else if ( !myHighlitableActor->myExtractUnstructuredGrid->GetInput() )
+      //   myHighlitableActor->SetUnstructuredGrid(myVisualObj->GetUnstructuredGrid());
+
       if(myIsHighlighted) {
         myHighlitableActor->SetProperty(myHighlightProp);
       }else if(myIsPreselected){
@@ -1868,6 +1896,24 @@ void SMESH_ActorDef::UpdateHighlight()
   }
 }
 
+void SMESH_ActorDef::EnableSelection( bool enable )
+{
+  // selection in the Viewer enabled/disabled
+  if ( enable && ! myBaseActor->myExtractUnstructuredGrid->GetInput() )
+  {
+    myBaseActor->SetUnstructuredGrid(myVisualObj->GetUnstructuredGrid());
+    myHighlitableActor->SetUnstructuredGrid(myVisualObj->GetUnstructuredGrid());
+    myBaseActor->myExtractUnstructuredGrid->Update();
+    myHighlitableActor->myExtractUnstructuredGrid->Update();
+  }
+  if ( !enable && myBaseActor->myExtractUnstructuredGrid->GetInput() )
+  {
+    myBaseActor->SetUnstructuredGrid( NULL );
+    myHighlitableActor->SetUnstructuredGrid( NULL );
+    myBaseActor->myExtractUnstructuredGrid->Update();
+    myHighlitableActor->myExtractUnstructuredGrid->Update();
+  }
+}
 
 void SMESH_ActorDef::highlight(bool theHighlight)
 {
@@ -2297,6 +2343,11 @@ void SMESH_ActorDef::SetOpenGLClippingPlane()
   myHighlitableActor->SetPlaneCollection( myPlaneCollection );
   myHighlitableActor->SetUnstructuredGrid(myVisualObj->GetUnstructuredGrid());
 
+  if ( !mySelector || !mySelector->IsSelectionEnabled() )
+  {
+    myBaseActor->SetUnstructuredGrid( NULL );
+    myHighlitableActor->SetUnstructuredGrid( NULL );
+  }
   my1DActor->SetPlaneCollection( myPlaneCollection );
   my1DActor->SetUnstructuredGrid(myVisualObj->GetUnstructuredGrid());
 
diff --git a/src/OBJECT/SMESH_ActorDef.h b/src/OBJECT/SMESH_ActorDef.h
index eb3654ab2..4366a98a6 100644
--- a/src/OBJECT/SMESH_ActorDef.h
+++ b/src/OBJECT/SMESH_ActorDef.h
@@ -95,6 +95,7 @@ class SMESH_ActorDef : public SMESH_Actor
   virtual void AddToRender(vtkRenderer* theRenderer); 
   virtual void RemoveFromRender(vtkRenderer* theRenderer);
 
+  virtual void EnableSelection( bool enable );
   virtual bool hasHighlight() { return true; }  
   virtual void highlight(bool theHighlight);  
   virtual void SetPreSelected(bool thePreselect = false);
diff --git a/src/OBJECT/SMESH_DeviceActor.cxx b/src/OBJECT/SMESH_DeviceActor.cxx
index f9195f19f..2d632782d 100644
--- a/src/OBJECT/SMESH_DeviceActor.cxx
+++ b/src/OBJECT/SMESH_DeviceActor.cxx
@@ -204,7 +204,6 @@ SMESH_DeviceActor
   SetUnstructuredGrid(myVisualObj->GetUnstructuredGrid());
 }
 
-
 void
 SMESH_DeviceActor
 ::SetImplicitFunctionUsed(bool theIsImplicitFunctionUsed)
@@ -224,14 +223,14 @@ void
 SMESH_DeviceActor
 ::SetUnstructuredGrid(vtkUnstructuredGrid* theGrid)
 {
-  if(theGrid){
-    //myIsShrinkable = theGrid->GetNumberOfCells() > 10;
+  myExtractUnstructuredGrid->SetInputData(theGrid);
+
+  if ( theGrid )
+  {
     myIsShrinkable = true;
 
-    myExtractUnstructuredGrid->SetInputData(theGrid);
-
     myMergeFilter->SetGeometryConnection(myExtractUnstructuredGrid->GetOutputPort());
-    
+
     //Pass diameters of the balls
     if(myMapper->GetBallEnabled()) {
       myMergeFilter->SetScalarsConnection(myExtractUnstructuredGrid->GetOutputPort());
@@ -242,7 +241,7 @@ SMESH_DeviceActor
     int anId = 0;
     SetImplicitFunctionUsed(myIsImplicitFunctionUsed);
     myPassFilter[ anId + 1]->SetInputConnection( myPassFilter[ anId ]->GetOutputPort() );
-    
+
     anId++; // 1
     myTransformFilter->SetInputConnection( myPassFilter[ anId ]->GetOutputPort() );
 
@@ -254,7 +253,7 @@ SMESH_DeviceActor
     myGeomFilter->SetInputConnection( myPassFilter[ anId ]->GetOutputPort() );
 
     anId++; // 4
-    myPassFilter[ anId ]->SetInputConnection( myGeomFilter->GetOutputPort() ); 
+    myPassFilter[ anId ]->SetInputConnection( myGeomFilter->GetOutputPort() );
     myPassFilter[ anId + 1 ]->SetInputConnection( myPassFilter[ anId ]->GetOutputPort() );
 
     anId++; // 5
@@ -263,8 +262,8 @@ SMESH_DeviceActor
       myMapper->SetClippingPlanes( myPlaneCollection );
 
     vtkLODActor::SetMapper( myMapper );
-    Modified();
   }
+  Modified();
 }
 
 void
@@ -281,6 +280,7 @@ SMESH_DeviceActor
   return myExtractUnstructuredGrid;
 }
 
+#include "SMDS_Mesh.hxx"
 
 vtkUnstructuredGrid* 
 SMESH_DeviceActor
@@ -607,10 +607,19 @@ SMESH_DeviceActor
 
 
 
-unsigned long int 
+unsigned long int
 SMESH_DeviceActor
 ::GetMTime()
 {
+  // cout << this->myExtractUnstructuredGrid
+  //      << " " << this->Superclass::GetMTime()
+  //      << " " << myExtractGeometry->GetMTime()
+  //      << " " << myExtractUnstructuredGrid->GetMTime()
+  //      << " " << myMergeFilter->GetMTime()
+  //      << " " << myGeomFilter->GetMTime()
+  //      << " " << myTransformFilter->GetMTime()
+  //      << " " << myFaceOrientationFilter->GetMTime() << endl;
+
   unsigned long mTime = this->Superclass::GetMTime();
   mTime = max(mTime,myExtractGeometry->GetMTime());
   mTime = max(mTime,myExtractUnstructuredGrid->GetMTime());
@@ -718,7 +727,7 @@ SMESH_DeviceActor
 ::UpdateFaceOrientation()
 {
   bool aShowFaceOrientation = myIsFacesOriented;
-  aShowFaceOrientation &= GetVisibility();
+  aShowFaceOrientation &= vtkLODActor::GetVisibility(); //GetVisibility(); -- avoid calling GetUnstructuredGrid()  
   aShowFaceOrientation &= myRepresentation == eSurface;
   myFaceOrientation->SetVisibility(aShowFaceOrientation);
 }
@@ -762,8 +771,9 @@ void
 SMESH_DeviceActor
 ::SetVisibility(int theMode)
 {
-  if(!myExtractUnstructuredGrid->GetInput() || 
-     GetUnstructuredGrid()->GetNumberOfCells())
+  if(( theMode ) &&
+     ( !myExtractUnstructuredGrid->GetInput() || 
+       GetUnstructuredGrid()->GetNumberOfCells()))
   {
     vtkLODActor::SetVisibility(theMode);
   }else{
@@ -777,10 +787,12 @@ int
 SMESH_DeviceActor
 ::GetVisibility()
 {
-  if(!GetUnstructuredGrid()->GetNumberOfCells()){
+  int visibi = vtkLODActor::GetVisibility();
+  if(visibi && !GetUnstructuredGrid()->GetNumberOfCells()){
     vtkLODActor::SetVisibility(false);
+    visibi = 0;
   }
-  return vtkLODActor::GetVisibility();
+  return visibi;
 }
 
 
@@ -821,7 +833,7 @@ SMESH_DeviceActor
 {
   vtkDataSet* aDataSet = myMergeFilter->GetOutput();
   vtkIdType anID = myVisualObj->GetNodeVTKId(theObjID);
-  double* aCoord = (anID >=0) ? aDataSet->GetPoint(anID) : NULL;
+  double* aCoord = (anID >=0 && anID < aDataSet->GetNumberOfPoints()) ? aDataSet->GetPoint(anID) : NULL;
   if(MYDEBUG) MESSAGE("GetNodeCoord - theObjID = "<<theObjID<<"; anID = "<<anID);
   return aCoord;
 }
diff --git a/src/OBJECT/SMESH_Object.cxx b/src/OBJECT/SMESH_Object.cxx
index 520abe335..3b9cd0b8c 100644
--- a/src/OBJECT/SMESH_Object.cxx
+++ b/src/OBJECT/SMESH_Object.cxx
@@ -719,7 +719,7 @@ bool SMESH_MeshObj::NulData()
     points->SetNumberOfPoints(0);
     myEmptyGrid->SetPoints( points );
     points->Delete();
-    myEmptyGrid->BuildLinks();
+    //myEmptyGrid->BuildLinks();
   }
   myGrid->ShallowCopy(myEmptyGrid);
   return true;
diff --git a/src/OBJECT/SMESH_SVTKActor.cxx b/src/OBJECT/SMESH_SVTKActor.cxx
index 66c7b738b..a9a549f03 100644
--- a/src/OBJECT/SMESH_SVTKActor.cxx
+++ b/src/OBJECT/SMESH_SVTKActor.cxx
@@ -119,11 +119,10 @@ SMESH_SVTKActor
   myBallGrid->Initialize();
   myBallGrid->Allocate();
 
-  vtkDataSet *aSourceDataSet = theMapActor->GetInput();
-  SVTK::CopyPoints( GetSource(), aSourceDataSet );
-  SVTK::CopyPoints( myBallGrid, aSourceDataSet );
-  SVTK::CopyPoints( my0DGrid,    aSourceDataSet );
-
+  vtkUnstructuredGrid * aSourceGrid = (vtkUnstructuredGrid *)theMapActor->GetInput();
+  GetSource()->SetPoints( aSourceGrid->GetPoints() );
+  myBallGrid->SetPoints( aSourceGrid->GetPoints() );
+  my0DGrid->SetPoints( aSourceGrid->GetPoints() );
 
   int aNbOfParts = theMapIndex.Extent();
 
@@ -132,7 +131,7 @@ SMESH_SVTKActor
   //Copy deamaters of the balls
   if(myVisualObj) {
     outputCD = myBallGrid->GetCellData();
-    cd = aSourceDataSet->GetCellData();
+    cd = aSourceGrid->GetCellData();
   }
   outputCD->CopyAllocate(cd,aNbOfParts,aNbOfParts/2);
   for(int ind = 1; ind <= aNbOfParts; ind++){
diff --git a/src/SMDS/SMDS_Mesh.cxx b/src/SMDS/SMDS_Mesh.cxx
index 95871d37a..34d9da63d 100644
--- a/src/SMDS/SMDS_Mesh.cxx
+++ b/src/SMDS/SMDS_Mesh.cxx
@@ -160,7 +160,7 @@ SMDS_Mesh::SMDS_Mesh():
   points->SetNumberOfPoints(0 /*SMDS_Mesh::chunkSize*/);
   myGrid->SetPoints( points );
   points->Delete();
-  myGrid->BuildLinks();
+  //myGrid->BuildLinks();
   this->Modified();
 
   // initialize static maps in SMDS_MeshCell, to be thread-safe
@@ -2757,7 +2757,7 @@ void SMDS_Mesh::Clear()
   points->SetNumberOfPoints(0 /*SMDS_Mesh::chunkSize*/);
   myGrid->SetPoints( points );
   points->Delete();
-  myGrid->BuildLinks();
+  myGrid->DeleteLinks();
 }
 
 ///////////////////////////////////////////////////////////////////////////////
@@ -4702,7 +4702,7 @@ void SMDS_Mesh::dumpGrid(string ficdump)
     ficcon << endl;
   }
   ficcon << "-------------------------------- connectivity " <<  nbPoints << endl;
-  vtkCellLinks *links = myGrid->GetCellLinks();
+  vtkCellLinks *links = myGrid->GetLinks();
   for (int i=0; i<nbPoints; i++)
   {
     int ncells = links->GetNcells(i);
@@ -4711,8 +4711,8 @@ void SMDS_Mesh::dumpGrid(string ficdump)
     for (int j=0; j<ncells; j++)
     {
       ficcon << " " << cells[j];
-        }
-        ficcon << endl;
+    }
+    ficcon << endl;
   }
   ficcon.close();
 
@@ -4720,7 +4720,7 @@ void SMDS_Mesh::dumpGrid(string ficdump)
 
 void SMDS_Mesh::compactMesh()
 {
-  MESSAGE("SMDS_Mesh::compactMesh do nothing!");
+  this->myCompactTime = this->myModifTime;
 }
 
 int SMDS_Mesh::fromVtkToSmds(int vtkid)
@@ -4780,10 +4780,5 @@ unsigned long SMDS_Mesh::GetMTime() const
 
 bool SMDS_Mesh::isCompacted()
 {
-  if (this->myModifTime > this->myCompactTime)
-  {
-    this->myCompactTime = this->myModifTime;
-    return false;
-  }
-  return true;
+  return this->myCompactTime == this->myModifTime;
 }
diff --git a/src/SMDS/SMDS_MeshNode.cxx b/src/SMDS/SMDS_MeshNode.cxx
index 5499f8b7d..77858f173 100644
--- a/src/SMDS/SMDS_MeshNode.cxx
+++ b/src/SMDS/SMDS_MeshNode.cxx
@@ -62,16 +62,12 @@ SMDS_MeshNode::SMDS_MeshNode(int id, int meshId, int shapeId, double x, double y
 void SMDS_MeshNode::init(int id, int meshId, int shapeId, double x, double y, double z)
 {
   SMDS_MeshElement::init(id, meshId, shapeId);
-  myVtkID = id -1;
+  myVtkID = id - 1;
   assert(myVtkID >= 0);
-  //MESSAGE("Node " << myID << " " << myVtkID << " (" << x << ", " << y << ", " << z << ")");
-  SMDS_Mesh* mesh = SMDS_Mesh::_meshList[myMeshId];
-  SMDS_UnstructuredGrid * grid = mesh->getGrid();
+  SMDS_UnstructuredGrid * grid = SMDS_Mesh::_meshList[myMeshId]->getGrid();
   vtkPoints *points = grid->GetPoints();
   points->InsertPoint(myVtkID, x, y, z);
-  SMDS_CellLinks *cellLinks = dynamic_cast<SMDS_CellLinks*>(grid->GetCellLinks());
-  assert(cellLinks);
-  cellLinks->ResizeForPoint( myVtkID );
+  grid->GetLinks()->ResizeForPoint( myVtkID );
 }
 
 SMDS_MeshNode::~SMDS_MeshNode()
@@ -91,7 +87,8 @@ void SMDS_MeshNode::RemoveInverseElement(const SMDS_MeshElement * parent)
   //MESSAGE("RemoveInverseElement " << myID << " " << parent->GetID());
   const SMDS_MeshCell* cell = dynamic_cast<const SMDS_MeshCell*>(parent);
   MYASSERT(cell);
-  SMDS_Mesh::_meshList[myMeshId]->getGrid()->RemoveReferenceToCell(myVtkID, cell->getVtkId());
+  if ( SMDS_Mesh::_meshList[myMeshId]->getGrid()->HasLinks() )
+    SMDS_Mesh::_meshList[myMeshId]->getGrid()->RemoveReferenceToCell(myVtkID, cell->getVtkId());
 }
 
 //=======================================================================
@@ -189,7 +186,7 @@ public:
 
 SMDS_ElemIteratorPtr SMDS_MeshNode::GetInverseElementIterator(SMDSAbs_ElementType type) const
 {
-  vtkCellLinks::Link l = SMDS_Mesh::_meshList[myMeshId]->getGrid()->GetCellLinks()->GetLink(myVtkID);
+  vtkCellLinks::Link l = SMDS_Mesh::_meshList[myMeshId]->getGrid()->GetLinks()->GetLink(myVtkID);
   return SMDS_ElemIteratorPtr(new SMDS_MeshNode_MyInvIterator(SMDS_Mesh::_meshList[myMeshId], l.cells, l.ncells, type));
 }
 
@@ -248,7 +245,7 @@ elementsIterator(SMDSAbs_ElementType type) const
     return SMDS_MeshElement::elementsIterator(SMDSAbs_Node);
   else
   {
-    vtkCellLinks::Link l = SMDS_Mesh::_meshList[myMeshId]->getGrid()->GetCellLinks()->GetLink(myVtkID);
+    vtkCellLinks::Link l = SMDS_Mesh::_meshList[myMeshId]->getGrid()->GetLinks()->GetLink(myVtkID);
     return SMDS_ElemIteratorPtr(new SMDS_MeshNode_MyIterator(SMDS_Mesh::_meshList[myMeshId], l.cells, l.ncells, type));
   }
 }
@@ -319,7 +316,7 @@ void SMDS_MeshNode::AddInverseElement(const SMDS_MeshElement* ME)
   const SMDS_MeshCell *cell = dynamic_cast<const SMDS_MeshCell*> (ME);
   assert(cell);
   SMDS_UnstructuredGrid* grid = SMDS_Mesh::_meshList[myMeshId]->getGrid();
-  vtkCellLinks *Links = grid->GetCellLinks();
+  vtkCellLinks *Links = grid->GetLinks();
   Links->ResizeCellList(myVtkID, 1);
   Links->AddCellReference(cell->getVtkId(), myVtkID);
 }
@@ -335,7 +332,7 @@ void SMDS_MeshNode::ClearInverseElements()
 
 bool SMDS_MeshNode::emptyInverseElements()
 {
-  vtkCellLinks::Link l = SMDS_Mesh::_meshList[myMeshId]->getGrid()->GetCellLinks()->GetLink(myVtkID);
+  vtkCellLinks::Link l = SMDS_Mesh::_meshList[myMeshId]->getGrid()->GetLinks()->GetLink(myVtkID);
   return (l.ncells == 0);
 }
 
@@ -347,7 +344,7 @@ bool SMDS_MeshNode::emptyInverseElements()
 
 int SMDS_MeshNode::NbInverseElements(SMDSAbs_ElementType type) const
 {
-  vtkCellLinks::Link l = SMDS_Mesh::_meshList[myMeshId]->getGrid()->GetCellLinks()->GetLink(myVtkID);
+  vtkCellLinks::Link l = SMDS_Mesh::_meshList[myMeshId]->getGrid()->GetLinks()->GetLink(myVtkID);
 
   if ( type == SMDSAbs_All )
     return l.ncells;
diff --git a/src/SMDS/SMDS_UnstructuredGrid.cxx b/src/SMDS/SMDS_UnstructuredGrid.cxx
index 808d809a1..1f0f79941 100644
--- a/src/SMDS/SMDS_UnstructuredGrid.cxx
+++ b/src/SMDS/SMDS_UnstructuredGrid.cxx
@@ -53,6 +53,51 @@ void SMDS_CellLinks::ResizeForPoint(vtkIdType vtkID)
   }
 }
 
+void SMDS_CellLinks::BuildLinks(vtkDataSet *data, vtkCellArray *Connectivity, vtkUnsignedCharArray* types)
+{
+  // build links taking into account removed cells
+
+  vtkIdType numPts = data->GetNumberOfPoints();
+  vtkIdType j, cellId = 0;
+  unsigned short *linkLoc;
+  vtkIdType npts=0;
+  vtkIdType *pts=0;
+  vtkIdType loc = Connectivity->GetTraversalLocation();
+
+  // traverse data to determine number of uses of each point
+  cellId = 0;
+  for (Connectivity->InitTraversal();
+       Connectivity->GetNextCell(npts,pts); cellId++)
+  {
+    if ( types->GetValue( cellId ) != VTK_EMPTY_CELL )
+      for (j=0; j < npts; j++)
+      {
+        this->IncrementLinkCount(pts[j]);
+      }
+  }
+
+  // now allocate storage for the links
+  this->AllocateLinks(numPts);
+  this->MaxId = numPts - 1;
+
+  // fill out lists with references to cells
+  linkLoc = new unsigned short[numPts];
+  memset(linkLoc, 0, numPts*sizeof(unsigned short));
+
+  cellId = 0;
+  for (Connectivity->InitTraversal();
+       Connectivity->GetNextCell(npts,pts); cellId++)
+  {
+    if ( types->GetValue( cellId ) != VTK_EMPTY_CELL )
+      for (j=0; j < npts; j++)
+      {
+        this->InsertCellReference(pts[j], (linkLoc[pts[j]])++, cellId);
+      }
+  }
+  delete [] linkLoc;
+  Connectivity->SetTraversalLocation(loc);
+}
+
 SMDS_CellLinks::SMDS_CellLinks() :
   vtkCellLinks()
 {
@@ -149,6 +194,8 @@ void SMDS_UnstructuredGrid::compactGrid(std::vector<int>& idNodesOldToNew, int n
   //MESSAGE("------------------------- compactGrid " << newNodeSize << " " << newCellSize);//CHRONO(1);
   int alreadyCopied = 0;
 
+  this->DeleteLinks();
+
   // --- if newNodeSize, create a new compacted vtkPoints
 
   vtkPoints *newPoints = vtkPoints::New();
@@ -187,6 +234,12 @@ void SMDS_UnstructuredGrid::compactGrid(std::vector<int>& idNodesOldToNew, int n
 
   int oldCellSize = this->Types->GetNumberOfTuples();
 
+  if ( oldCellSize == newCellSize )
+  {
+    for ( int i = 0; i < oldCellSize; ++i )
+      idCellsOldToNew[i] = i;
+    return;
+  }
   vtkCellArray *newConnectivity = vtkCellArray::New();
   newConnectivity->Initialize();
   int oldCellDataSize = this->Connectivity->GetData()->GetSize();
@@ -287,7 +340,6 @@ void SMDS_UnstructuredGrid::compactGrid(std::vector<int>& idNodesOldToNew, int n
   newTypes->Delete();
   newLocations->Delete();
   newConnectivity->Delete();
-  this->BuildLinks();
 }
 
 void SMDS_UnstructuredGrid::copyNodes(vtkPoints *       newPoints,
@@ -975,17 +1027,34 @@ void SMDS_UnstructuredGrid::BuildLinks()
 {
   // Remove the old links if they are already built
   if (this->Links)
-    {
+  {
     this->Links->UnRegister(this);
-    }
+  }
 
-  this->Links = SMDS_CellLinks::New();
+  SMDS_CellLinks* links;
+  this->Links = links = SMDS_CellLinks::New();
   this->Links->Allocate(this->GetNumberOfPoints());
   this->Links->Register(this);
-  this->Links->BuildLinks(this, this->Connectivity);
+  links->BuildLinks(this, this->Connectivity,this->GetCellTypesArray() );
   this->Links->Delete();
 }
 
+void SMDS_UnstructuredGrid::DeleteLinks()
+{
+  // Remove the old links if they are already built
+  if (this->Links)
+  {
+    this->Links->UnRegister(this);
+    this->Links = NULL;
+  }
+}
+SMDS_CellLinks* SMDS_UnstructuredGrid::GetLinks()
+{
+  if ( !this->Links )
+    BuildLinks();
+  return static_cast< SMDS_CellLinks* >( this->Links );
+}
+
 /*! Create a volume (prism or hexahedron) by duplication of a face.
  * Designed for use in creation of flat elements separating volume domains.
  * A face separating two domains is shared by two volume cells.
diff --git a/src/SMDS/SMDS_UnstructuredGrid.hxx b/src/SMDS/SMDS_UnstructuredGrid.hxx
index f2ad6bd57..d34095d9a 100644
--- a/src/SMDS/SMDS_UnstructuredGrid.hxx
+++ b/src/SMDS/SMDS_UnstructuredGrid.hxx
@@ -54,6 +54,7 @@ class SMDS_EXPORT SMDS_CellLinks: public vtkCellLinks
 {
 public:
   void ResizeForPoint(vtkIdType vtkID);
+  void BuildLinks(vtkDataSet *data, vtkCellArray *Connectivity, vtkUnsignedCharArray* types);
   static SMDS_CellLinks* New();
 protected:
   SMDS_CellLinks();
@@ -88,15 +89,15 @@ public:
   void GetNodeIds(std::set<int>& nodeSet, int downId, unsigned char downType);
   void ModifyCellNodes(int vtkVolId, std::map<int, int> localClonedNodeIds);
   int getOrderedNodesOfFace(int vtkVolId, int& dim, std::vector<vtkIdType>& orderedNodes);
-  void BuildLinks();
   SMDS_MeshCell* extrudeVolumeFromFace(int vtkVolId, int domain1, int domain2,
                                        std::set<int>&                      originalNodes,
                                        std::map<int, std::map<int, int> >& nodeDomains,
                                        std::map<int, std::map<long,int> >& nodeQuadDomains);
-  vtkCellLinks* GetLinks()
-  {
-    return Links;
-  }
+  void BuildLinks();
+  void DeleteLinks();
+  SMDS_CellLinks* GetLinks();
+  bool HasLinks() const { return this->Links; }
+
   SMDS_Downward* getDownArray(unsigned char vtkType)
   {
     return _downArray[vtkType];
diff --git a/src/SMESH/SMESH_Gen.cxx b/src/SMESH/SMESH_Gen.cxx
index 9eadd2d60..504089aea 100644
--- a/src/SMESH/SMESH_Gen.cxx
+++ b/src/SMESH/SMESH_Gen.cxx
@@ -123,13 +123,16 @@ SMESH_Mesh* SMESH_Gen::CreateMesh(int theStudyId, bool theIsEmbeddedMode)
 
 bool SMESH_Gen::Compute(SMESH_Mesh &          aMesh,
                         const TopoDS_Shape &  aShape,
-                        const bool            aShapeOnly /*=false*/,
-                        const bool            anUpward /*=false*/,
+                        const int             aFlags /*= COMPACT_MESH*/,
                         const ::MeshDimension aDim /*=::MeshDim_3D*/,
                         TSetOfInt*            aShapesId /*=0*/)
 {
   MEMOSTAT;
 
+  const bool   aShapeOnly = aFlags & SHAPE_ONLY;
+  const bool     anUpward = aFlags & UPWARD;
+  const bool aCompactMesh = aFlags & COMPACT_MESH;
+
   bool ret = true;
 
   SMESH_subMesh *sm = aMesh.GetSubMesh(aShape);
@@ -141,7 +144,7 @@ bool SMESH_Gen::Compute(SMESH_Mesh &          aMesh,
   SMESH_subMeshIteratorPtr smIt;
 
   // Fix of Issue 22150. Due to !BLSURF->OnlyUnaryInput(), BLSURF computes edges
-  // that must be computed by Projection 1D-2D when Projection asks to compute
+  // that must be computed by Projection 1D-2D while the Projection asks to compute
   // one face only.
   SMESH_subMesh::compute_event computeEvent =
     aShapeOnly ? SMESH_subMesh::COMPUTE_SUBMESH : SMESH_subMesh::COMPUTE;
@@ -331,7 +334,7 @@ bool SMESH_Gen::Compute(SMESH_Mesh &          aMesh,
             SMESH_Hypothesis::Hypothesis_Status status;
             if ( subAlgo->CheckHypothesis( aMesh, aSubShape, status ))
               // mesh a lower smToCompute starting from vertices
-              Compute( aMesh, aSubShape, true, /*anUpward=*/true, aDim, aShapesId );
+              Compute( aMesh, aSubShape, aFlags | SHAPE_ONLY_UPWARD, aDim, aShapesId );
               // Compute( aMesh, aSubShape, aShapeOnly, /*anUpward=*/true, aDim, aShapesId );
           }
         }
@@ -363,17 +366,17 @@ bool SMESH_Gen::Compute(SMESH_Mesh &          aMesh,
     // -----------------------------------------------
     // mesh the rest sub-shapes starting from vertices
     // -----------------------------------------------
-    ret = Compute( aMesh, aShape, aShapeOnly, /*anUpward=*/true, aDim, aShapesId );
+    ret = Compute( aMesh, aShape, aFlags | UPWARD, aDim, aShapesId );
   }
 
   MEMOSTAT;
 
-  SMESHDS_Mesh *myMesh = aMesh.GetMeshDS();
-  //MESSAGE("*** compactMesh after compute");
-  myMesh->compactMesh();
+  if ( aCompactMesh )
+    aMesh.GetMeshDS()->compactMesh();
 
   // fix quadratic mesh by bending iternal links near concave boundary
-  if ( aShape.IsSame( aMesh.GetShapeToMesh() ) &&
+  if ( aCompactMesh && // a final compute
+       aShape.IsSame( aMesh.GetShapeToMesh() ) &&
        !aShapesId && // not preview
        ret ) // everything is OK
   {
diff --git a/src/SMESH/SMESH_Gen.hxx b/src/SMESH/SMESH_Gen.hxx
index e047be38f..eb6934595 100644
--- a/src/SMESH/SMESH_Gen.hxx
+++ b/src/SMESH/SMESH_Gen.hxx
@@ -69,19 +69,25 @@ public:
   SMESH_Mesh* CreateMesh(int theStudyId, bool theIsEmbeddedMode)
     throw(SALOME_Exception);
 
+  enum ComputeFlags
+  {
+    SHAPE_ONLY        = 1, // to ignore algo->OnlyUnaryInput() feature and to compute a given shape only.
+    UPWARD            = 2, // to compute from vertices up to more complex shape (internal usage)
+    COMPACT_MESH      = 4, // to compact the mesh at the end
+    SHAPE_ONLY_UPWARD = 3  // SHAPE_ONLY | UPWARD
+  };
   /*!
    * \brief Computes aMesh on aShape 
-   *  \param aShapeOnly - if true, algo->OnlyUnaryInput() feature is ignored and
-   *                      only \a aShape is computed.
-   *  \param anUpward - compute from vertices up to more complex shape (internal usage)
-   *  \param aDim - upper level dimension of the mesh computation
+   *  \param aMesh - the mesh.
+   *  \param aShape - the shape.
+   *  \param aFlags - ComputeFlags. By default compute the whole mesh and compact at the end.
+   *  \param aDim - upper level dimension of the mesh computation (for preview)
    *  \param aShapesId - list of shapes with computed mesh entities (elements or nodes)
-   *  \retval bool - true if none submesh failed to compute
+   *  \retval bool - true if none sub-mesh failed to compute
    */
   bool Compute(::SMESH_Mesh &        aMesh,
                const TopoDS_Shape &  aShape,
-               const bool            aShapeOnly=false,
-               const bool            anUpward=false,
+               const int             aFlags = COMPACT_MESH,
                const ::MeshDimension aDim=::MeshDim_3D,
                TSetOfInt*            aShapesId=0);
 
diff --git a/src/SMESH/SMESH_MeshEditor.cxx b/src/SMESH/SMESH_MeshEditor.cxx
index faeeefc01..056da7050 100644
--- a/src/SMESH/SMESH_MeshEditor.cxx
+++ b/src/SMESH/SMESH_MeshEditor.cxx
@@ -11650,7 +11650,7 @@ bool SMESH_MeshEditor::DoubleNodesOnGroupBoundaries( const std::vector<TIDSorted
   }
 
   meshDS->CleanDownWardConnectivity(); // Mesh has been modified, downward connectivity is no more usable, free memory
-  grid->BuildLinks();
+  grid->DeleteLinks();
 
   CHRONOSTOP(50);
   counters::stats();
diff --git a/src/SMESHDS/SMESHDS_Mesh.cxx b/src/SMESHDS/SMESHDS_Mesh.cxx
index b0df38a21..ad235f0b8 100644
--- a/src/SMESHDS/SMESHDS_Mesh.cxx
+++ b/src/SMESHDS/SMESHDS_Mesh.cxx
@@ -2145,10 +2145,13 @@ SMDS_MeshVolume* SMESHDS_Mesh::AddVolumeWithID(const SMDS_MeshNode * n1,
 
 void SMESHDS_Mesh::compactMesh()
 {
+  if ( isCompacted() )
+    return;
+  SMDS_Mesh::compactMesh();
+
   int newNodeSize = 0;
   int nbNodes = myNodes.size();
   int nbVtkNodes = myGrid->GetNumberOfPoints();
-  //MESSAGE("nbNodes=" << nbNodes << " nbVtkNodes=" << nbVtkNodes);
   int nbNodeTemp = nbVtkNodes;
   if (nbNodes > nbVtkNodes)
     nbNodeTemp = nbNodes;
@@ -2166,13 +2169,11 @@ void SMESHDS_Mesh::compactMesh()
     }
   }
   bool areNodesModified = (newNodeSize < nbVtkNodes);
-  //MESSAGE("------------------------- compactMesh Nodes Modified: " << areNodesModified);
   areNodesModified = true;
 
   int newCellSize = 0;
   int nbCells = myCells.size();
   int nbVtkCells = myGrid->GetNumberOfCells();
-  //MESSAGE("nbCells=" << nbCells << " nbVtkCells=" << nbVtkCells);
   int nbCellTemp = nbVtkCells;
   if (nbCells > nbVtkCells)
     nbCellTemp = nbCells;
@@ -2184,9 +2185,6 @@ void SMESHDS_Mesh::compactMesh()
   {
     if (myCells[i])
     {
-      //          //idCellsOldToNew[i] = myCellIdVtkToSmds[i]; // valid vtk indexes are > = 0
-      //          int vtkid = myCells[i]->getVtkId();
-      //          idCellsOldToNew[vtkid] = i; // old vtkId --> old smdsId (not used in input)
       newCellSize++;
     }
   }
@@ -2212,7 +2210,6 @@ void SMESHDS_Mesh::compactMesh()
 
   if (areNodesModified)
   {
-    //MESSAGE("-------------- modify myNodes");
     SetOfNodes newNodes;
     newNodes.resize(newNodeSize+1,0); // 0 not used, SMDS numbers 1..n
     int newSmdsId = 0;
@@ -2223,16 +2220,13 @@ void SMESHDS_Mesh::compactMesh()
         newSmdsId++; // SMDS id start to 1
         int oldVtkId = myNodes[i]->getVtkId();
         int newVtkId = idNodesOldToNew[oldVtkId];
-        //MESSAGE("myNodes["<< i << "] vtkId " << oldVtkId << " --> " << newVtkId);
         myNodes[i]->setVtkId(newVtkId);
         myNodes[i]->setId(newSmdsId);
         newNodes[newSmdsId] = myNodes[i];
-        //MESSAGE("myNodes["<< i << "] --> newNodes[" << newSmdsId << "]");
       }
     }
     myNodes.swap(newNodes);
     this->myNodeIDFactory->emptyPool(newSmdsId); // newSmdsId = number of nodes
-    //MESSAGE("myNodes.size " << myNodes.size());
   }
 
   // --- SMDS_MeshCell, myCellIdVtkToSmds, myCellIdSmdsToVtk, myCells
@@ -2247,21 +2241,15 @@ void SMESHDS_Mesh::compactMesh()
       int newVtkId = idCellsOldToNew[oldVtkId];
       if (newVtkId > maxVtkId)
         maxVtkId = newVtkId;
-      //MESSAGE("myCells["<< oldSmdsId << "] vtkId " << oldVtkId << " --> " << newVtkId);
       myCells[oldSmdsId]->setVtkId(newVtkId);
     }
   }
-  //  MESSAGE("myCells.size()=" << myCells.size()
-  //          << " myCellIdSmdsToVtk.size()=" << myCellIdSmdsToVtk.size()
-  //          << " myCellIdVtkToSmds.size()=" << myCellIdVtkToSmds.size() );
 
   SetOfCells newCells;
-  //vector<int> newSmdsToVtk;
   vector<int> newVtkToSmds;
 
   assert(maxVtkId < newCellSize);
   newCells.resize(newCellSize+1, 0); // 0 not used, SMDS numbers 1..n
-  //newSmdsToVtk.resize(newCellSize+1, -1);
   newVtkToSmds.resize(newCellSize+1, -1);
 
   int myCellsSize = myCells.size();
@@ -2274,18 +2262,14 @@ void SMESHDS_Mesh::compactMesh()
       assert(newSmdsId <= newCellSize);
       newCells[newSmdsId] = myCells[i];
       newCells[newSmdsId]->setId(newSmdsId);
-      //MESSAGE("myCells["<< i << "] --> newCells[" << newSmdsId << "]");
       int idvtk = myCells[i]->getVtkId();
-      //newSmdsToVtk[newSmdsId] = idvtk;
       assert(idvtk < newCellSize);
       newVtkToSmds[idvtk] = newSmdsId;
     }
   }
 
   myCells.swap(newCells);
-  //myCellIdSmdsToVtk.swap(newSmdsToVtk);
   myCellIdVtkToSmds.swap(newVtkToSmds);
-  //MESSAGE("myCells.size()="<< myCells.size()<<" myCellIdVtkToSmds.size()="<<myCellIdVtkToSmds.size() );
   this->myElementIDFactory->emptyPool(newSmdsId);
 
   this->myScript->SetModified(true); // notify GUI client for buildPrs when update
diff --git a/src/SMESHGUI/SMESHGUI_Hypotheses.cxx b/src/SMESHGUI/SMESHGUI_Hypotheses.cxx
index 07757c909..b1f0e20fa 100644
--- a/src/SMESHGUI/SMESHGUI_Hypotheses.cxx
+++ b/src/SMESHGUI/SMESHGUI_Hypotheses.cxx
@@ -316,10 +316,10 @@ void SMESHGUI_GenericHypothesisCreator::onDialogFinished( int result )
           aMesh = aSubMesh->GetFather();
         _PTR(SObject) meshSO = SMESH::FindSObject( aMesh );
         SMESH::ModifiedMesh( meshSO, false, aMesh->NbNodes()==0);
-	SMESH_Actor* actor = SMESH::FindActorByEntry( meshSO->GetID().c_str() );
-	if( actor ) {
-	  actor->Update();
-	}
+        SMESH_Actor* actor = SMESH::FindActorByEntry( meshSO->GetID().c_str() );
+        if( actor ) {
+          actor->Update();
+        }
       }
   }
   SMESHGUI::GetSMESHGUI()->updateObjBrowser( true, 0 );
diff --git a/src/SMESHGUI/SMESHGUI_MeshInfo.cxx b/src/SMESHGUI/SMESHGUI_MeshInfo.cxx
index 4d7f87a98..db07868ad 100644
--- a/src/SMESHGUI/SMESHGUI_MeshInfo.cxx
+++ b/src/SMESHGUI/SMESHGUI_MeshInfo.cxx
@@ -2919,33 +2919,40 @@ SMESHGUI_MeshInfoDlg::~SMESHGUI_MeshInfoDlg()
 */
 void SMESHGUI_MeshInfoDlg::showInfo( const Handle(SALOME_InteractiveObject)& IO )
 {
+  if ( !IO.IsNull() )
+    myIO = IO;
+
   SMESH::SMESH_IDSource_var obj = SMESH::IObjectToInterface<SMESH::SMESH_IDSource>( IO );
-  if ( !CORBA::is_nil( obj ) ) {
+  if ( !CORBA::is_nil( obj ) )
+  {
     myAddInfo->showInfo( obj );  // nb of nodes in a group can be computed by myAddInfo,
     myBaseInfo->showInfo( obj ); // and it will be used by myBaseInfo (IPAL52871)
-    myCtrlInfo->showInfo( obj );
+    if ( myTabWidget->currentIndex() == CtrlInfo )
+      myCtrlInfo->showInfo( obj );
 
-    myActor = SMESH::FindActorByEntry( IO->getEntry() );
-    SVTK_Selector* selector = SMESH::GetSelector();
-    QString ID;
-    int nb = 0;
-    if ( myActor && selector ) {
-      nb = myMode->checkedId() == NodeMode ? 
-        SMESH::GetNameOfSelectedElements( selector, IO, ID ) :
-        SMESH::GetNameOfSelectedNodes( selector, IO, ID );
-    }
-    myElemInfo->setSource( myActor ) ;
-    if ( nb > 0 ) {
-      myID->setText( ID.trimmed() );
-      QSet<long> ids;
-      QStringList idTxt = ID.split( " ", QString::SkipEmptyParts );
-      foreach ( ID, idTxt )
-        ids << ID.trimmed().toLong();
-      myElemInfo->showInfo( ids, myMode->checkedId() == ElemMode );
-    }
-    else {
-      myID->clear();
-      myElemInfo->clear();
+    {
+      myActor = SMESH::FindActorByEntry( IO->getEntry() );
+      SVTK_Selector* selector = SMESH::GetSelector();
+      QString ID;
+      int nb = 0;
+      if ( myActor && selector ) {
+        nb = myMode->checkedId() == NodeMode ?
+          SMESH::GetNameOfSelectedElements( selector, IO, ID ) :
+          SMESH::GetNameOfSelectedNodes( selector, IO, ID );
+      }
+      myElemInfo->setSource( myActor ) ;
+      if ( nb > 0 ) {
+        myID->setText( ID.trimmed() );
+        QSet<long> ids;
+        QStringList idTxt = ID.split( " ", QString::SkipEmptyParts );
+        foreach ( ID, idTxt )
+          ids << ID.trimmed().toLong();
+        myElemInfo->showInfo( ids, myMode->checkedId() == ElemMode );
+      }
+      else {
+        myID->clear();
+        myElemInfo->clear();
+      }
     }
   }
 }
@@ -3049,11 +3056,9 @@ void SMESHGUI_MeshInfoDlg::updateInfo()
     Handle(SALOME_InteractiveObject) IO = selected.First();
     showInfo( IO );
   }
-//   else {
-//     myBaseInfo->clear();
-//     myElemInfo->clear();
-//     myAddInfo->clear();
-//   }
+  else {
+    showInfo( myIO );
+  }
 }
 
 /*!
diff --git a/src/SMESHGUI/SMESHGUI_MeshInfo.h b/src/SMESHGUI/SMESHGUI_MeshInfo.h
index dd1af5c02..2edf2e58a 100644
--- a/src/SMESHGUI/SMESHGUI_MeshInfo.h
+++ b/src/SMESHGUI/SMESHGUI_MeshInfo.h
@@ -395,6 +395,7 @@ private:
   SMESHGUI_AddInfo*  myAddInfo;
   SMESHGUI_CtrlInfo* myCtrlInfo;
   SMESH_Actor*       myActor;
+  Handle(SALOME_InteractiveObject) myIO;
 };
 
 class SMESHGUI_EXPORT SMESHGUI_CtrlInfoDlg : public QDialog
diff --git a/src/SMESH_I/SMESH_Gen_i.cxx b/src/SMESH_I/SMESH_Gen_i.cxx
index 983a3173b..8c44cfdd9 100644
--- a/src/SMESH_I/SMESH_Gen_i.cxx
+++ b/src/SMESH_I/SMESH_Gen_i.cxx
@@ -2001,7 +2001,7 @@ SMESH::MeshPreviewStruct* SMESH_Gen_i::Precompute( SMESH::SMESH_Mesh_ptr theMesh
       ::SMESH_Mesh& myLocMesh = meshServant->GetImpl();
       TSetOfInt shapeIds;
       ::MeshDimension aDim = (MeshDimension)theDimension;
-      if ( myGen.Compute( myLocMesh, myLocShape, false, false, aDim, &shapeIds ) )
+      if ( myGen.Compute( myLocMesh, myLocShape, ::SMESH_Gen::COMPACT_MESH, aDim, &shapeIds ) )
       {
         int nbShapeId = shapeIds.size();
         theShapesId.length( nbShapeId );
diff --git a/src/SMESH_I/SMESH_MeshEditor_i.cxx b/src/SMESH_I/SMESH_MeshEditor_i.cxx
index a99acd2f6..a0c252bd3 100644
--- a/src/SMESH_I/SMESH_MeshEditor_i.cxx
+++ b/src/SMESH_I/SMESH_MeshEditor_i.cxx
@@ -2952,8 +2952,9 @@ SMESH_MeshEditor_i::ExtrusionAlongPathObjects(const SMESH::ListOfIDSources & the
   }
 
   if ( !myIsPreviewMode ) {
-    aPythonDump << "(" << aGroups << ", error) = "
-                << this << ".ExtrusionAlongPathObjects( "
+    if ( aGroups->length() > 0 ) aPythonDump << "(" << aGroups << ", error) = ";
+    else                         aPythonDump << "(_noGroups, error) = ";
+    aPythonDump << this << ".ExtrusionAlongPathObjects( "
                 << theNodes            << ", "
                 << theEdges            << ", "
                 << theFaces            << ", "
diff --git a/src/StdMeshers/StdMeshers_QuadFromMedialAxis_1D2D.cxx b/src/StdMeshers/StdMeshers_QuadFromMedialAxis_1D2D.cxx
index 2fcf21902..76f3a31f2 100644
--- a/src/StdMeshers/StdMeshers_QuadFromMedialAxis_1D2D.cxx
+++ b/src/StdMeshers/StdMeshers_QuadFromMedialAxis_1D2D.cxx
@@ -383,7 +383,7 @@ namespace
         tmpMesh.ShapeToMesh( theEdges[i] );
         try {
           if ( !mesh->GetGen() ) continue; // tmp mesh
-          mesh->GetGen()->Compute( tmpMesh, theEdges[i], true, true ); // make nodes on VERTEXes
+          mesh->GetGen()->Compute( tmpMesh, theEdges[i], SMESH_Gen::SHAPE_ONLY_UPWARD ); // make nodes on VERTEXes
           if ( !algo->Compute( tmpMesh, theEdges[i] ))
             continue;
         }
@@ -868,7 +868,7 @@ namespace
     TmpMesh tmpMesh;
     tmpMesh.ShapeToMesh( branchEdge );
     try {
-      mesh->GetGen()->Compute( tmpMesh, branchEdge, true, true ); // make nodes on VERTEXes
+      mesh->GetGen()->Compute( tmpMesh, branchEdge, SMESH_Gen::SHAPE_ONLY_UPWARD ); // make nodes on VERTEXes
       if ( !algo->Compute( tmpMesh, branchEdge ))
         return false;
     }
@@ -1930,7 +1930,8 @@ namespace
     {
       if ( !theHasRadialHyp )
         // use global hyps
-        theHelper.GetGen()->Compute( *theHelper.GetMesh(), theShortEdges[i], true, true );
+        theHelper.GetGen()->Compute( *theHelper.GetMesh(), theShortEdges[i],
+                                     SMESH_Gen::SHAPE_ONLY_UPWARD );
 
       SMESH_subMesh* sm = theHelper.GetMesh()->GetSubMesh(theShortEdges[i] );
       if ( sm->IsEmpty() )
diff --git a/src/StdMeshers/StdMeshers_Regular_1D.cxx b/src/StdMeshers/StdMeshers_Regular_1D.cxx
index 8f4a10547..8a8bed9c0 100644
--- a/src/StdMeshers/StdMeshers_Regular_1D.cxx
+++ b/src/StdMeshers/StdMeshers_Regular_1D.cxx
@@ -675,7 +675,7 @@ bool StdMeshers_Regular_1D::computeInternalParameters(SMESH_Mesh &     theMesh,
   if ( !_mainEdge.IsNull() && _isPropagOfDistribution )
   {
     TopoDS_Edge mainEdge = TopoDS::Edge( _mainEdge ); // should not be a reference!
-    _gen->Compute( theMesh, mainEdge, /*aShapeOnly=*/true, /*anUpward=*/true);
+    _gen->Compute( theMesh, mainEdge, SMESH_Gen::SHAPE_ONLY_UPWARD );
 
     SMESHDS_SubMesh* smDS = theMesh.GetMeshDS()->MeshElements( mainEdge );
     if ( !smDS )