diff --git a/doc/salome/gui/SMESH/input/extrusion.doc b/doc/salome/gui/SMESH/input/extrusion.doc
index a28af48d4..126e3b0e9 100644
--- a/doc/salome/gui/SMESH/input/extrusion.doc
+++ b/doc/salome/gui/SMESH/input/extrusion.doc
@@ -3,8 +3,11 @@
 \page extrusion_page Extrusion
 
 \n Extrusion is used to build mesh elements of plus one
-dimension than the input ones. Any node, segment or 2D element can be
-extruded. Each type of elements has a corresponding type of extruded elements:
+dimension than the input ones. Boundary elements around elements of
+plus one dimension are additionally created. All created elements
+can be automatically grouped.
+<p>Any node, segment or 2D element can be extruded. Each type of
+elements is extruded into a corresponding type of result elements:
 <table>
 <tr><td><b>Extruded element</b></td><td><b> Result element </b></td></tr>
 <tr><td>Node              </td><td> Segment </td></tr>
diff --git a/src/SMESH/SMESH_MeshEditor.cxx b/src/SMESH/SMESH_MeshEditor.cxx
index 08cc1d9c2..75a8f216e 100644
--- a/src/SMESH/SMESH_MeshEditor.cxx
+++ b/src/SMESH/SMESH_MeshEditor.cxx
@@ -11247,6 +11247,14 @@ bool SMESH_MeshEditor::DoubleNodesOnGroupBoundaries( const std::vector<TIDSorted
         }
     }
 
+  // Remove empty groups (issue 0022812)
+  std::map<std::string, SMESH_Group*>::iterator name_group = mapOfJunctionGroups.begin();
+  for ( ; name_group != mapOfJunctionGroups.end(); ++name_group )
+  {
+    if ( name_group->second && name_group->second->GetGroupDS()->IsEmpty() )
+      myMesh->RemoveGroup( name_group->second->GetGroupDS()->GetID() );
+  }
+
   meshDS->CleanDownWardConnectivity(); // Mesh has been modified, downward connectivity is no more usable, free memory
   grid->BuildLinks();
 
diff --git a/src/SMESHGUI/SMESHGUI_DuplicateNodesDlg.cxx b/src/SMESHGUI/SMESHGUI_DuplicateNodesDlg.cxx
index 57428add2..8b3c6eac1 100644
--- a/src/SMESHGUI/SMESHGUI_DuplicateNodesDlg.cxx
+++ b/src/SMESHGUI/SMESHGUI_DuplicateNodesDlg.cxx
@@ -602,7 +602,7 @@ void SMESHGUI_DuplicateNodesDlg::onSelectionChanged()
         break;
       case 3:
         ok = ( aGroupType == SMESH::VOLUME || 
-	       aGroupType == SMESH::FACE );
+               aGroupType == SMESH::FACE );
         break;
       }
     }
diff --git a/src/SMESH_SWIG/smeshBuilder.py b/src/SMESH_SWIG/smeshBuilder.py
index fe63e726b..308472841 100644
--- a/src/SMESH_SWIG/smeshBuilder.py
+++ b/src/SMESH_SWIG/smeshBuilder.py
@@ -3391,7 +3391,7 @@ class Mesh:
     #  @param theSubMesh a group or a sub-mesh to convert; WARNING: in this case the mesh can become not conformal
     #  @param theToBiQuad If True, converts the mesh to bi-quadratic
     #  @ingroup l2_modif_tofromqu
-    def ConvertToQuadratic(self, theForce3d, theSubMesh=None, theToBiQuad=False):
+    def ConvertToQuadratic(self, theForce3d=False, theSubMesh=None, theToBiQuad=False):
         if isinstance( theSubMesh, Mesh ):
             theSubMesh = theSubMesh.mesh
         if theToBiQuad: