diff --git a/src/SMESHGUI/SMESHGUI_MeshOp.cxx b/src/SMESHGUI/SMESHGUI_MeshOp.cxx
index 111c5944f..ffca225e5 100644
--- a/src/SMESHGUI/SMESHGUI_MeshOp.cxx
+++ b/src/SMESHGUI/SMESHGUI_MeshOp.cxx
@@ -1,18 +1,18 @@
 // Copyright (C) 2005  OPEN CASCADE, EADS/CCR, LIP6, CEA/DEN,
 // CEDRAT, EDF R&D, LEG, PRINCIPIA R&D, BUREAU VERITAS
-// 
+//
 // This library is free software; you can redistribute it and/or
 // modify it under the terms of the GNU Lesser General Public
-// License as published by the Free Software Foundation; either 
+// License as published by the Free Software Foundation; either
 // version 2.1 of the License.
-// 
-// This library is distributed in the hope that it will be useful 
-// but WITHOUT ANY WARRANTY; without even the implied warranty of 
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU 
+//
+// This library is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 // Lesser General Public License for more details.
 //
-// You should have received a copy of the GNU Lesser General Public  
-// License along with this library; if not, write to the Free Software 
+// You should have received a copy of the GNU Lesser General Public
+// License along with this library; if not, write to the Free Software
 // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 //
 // See http://www.salome-platform.org/ or email : webmaster.salome@opencascade.com
@@ -81,7 +81,7 @@ enum { GLOBAL_ALGO_TAG        =3,
        SUBMESH_ON_SHELL_TAG   =8,
        SUBMESH_ON_SOLID_TAG   =9,
        SUBMESH_ON_COMPOUND_TAG=10 };
-       
+
 //================================================================================
 /*!
  * \brief Constructor
@@ -212,7 +212,7 @@ void SMESHGUI_MeshOp::startOperation()
     connect( myDlg, SIGNAL( hypoSet( const QString& )), SLOT( onHypoSet( const QString& )));
     connect( myDlg, SIGNAL( geomSelectionByMesh( bool )), SLOT( onGeomSelectionByMesh( bool )));
 
-    if ( myToCreate ) 
+    if ( myToCreate )
       if ( myIsMesh ) myHelpFileName = "/files/constructing_meshes.htm";
       else myHelpFileName = "/files/constructing_submeshes.htm";
     else myHelpFileName = "files/reassigning_hypotheses_and_algorithms.htm";
@@ -379,7 +379,7 @@ _PTR(SObject) SMESHGUI_MeshOp::getSubmeshByGeom() const
           }
         }
       }
-    }     
+    }
   }
   return _PTR(SObject)();
 }
@@ -421,7 +421,7 @@ void SMESHGUI_MeshOp::selectionDone()
       case GEOM::SOLID:
       case GEOM::SHELL:  shapeDim = 3; break;
       case GEOM::FACE:   shapeDim = 2; break;
-      case GEOM::WIRE:   
+      case GEOM::WIRE:
       case GEOM::EDGE:   shapeDim = 1; break;
       case GEOM::VERTEX: shapeDim = 0; break;
       default:
@@ -464,7 +464,7 @@ void SMESHGUI_MeshOp::selectionDone()
     {
       // if a submesh on the selected shape already exist, pass to submesh edition mode
       if ( _PTR(SObject) pSubmesh = getSubmeshByGeom() ) {
-        SMESH::SMESH_subMesh_var sm = 
+        SMESH::SMESH_subMesh_var sm =
           SMESH::SObjectToInterface<SMESH::SMESH_subMesh>( pSubmesh );
         bool editSubmesh = ( !sm->_is_nil() &&
                              SUIT_MessageBox::question2( myDlg, tr( "SMESH_WARNING" ),
@@ -586,7 +586,7 @@ bool SMESHGUI_MeshOp::isValid( QString& theMess ) const
       }
     }
   }
-    
+
   return true;
 }
 
@@ -756,7 +756,7 @@ SMESHGUI_MeshOp::getInitParamsHypothesis( const QString& aHypType,
   const int nbColonsInMeshEntry = 3;
   bool isSubMesh = myToCreate ?
     !myIsMesh :
-    myDlg->selectedObject( SMESHGUI_MeshDlg::Obj ).contains(':') > nbColonsInMeshEntry; 
+    myDlg->selectedObject( SMESHGUI_MeshDlg::Obj ).contains(':') > nbColonsInMeshEntry;
 
   if ( isSubMesh )
   {
@@ -797,7 +797,7 @@ SMESHGUI_MeshOp::getInitParamsHypothesis( const QString& aHypType,
 
 //================================================================================
 /*!
- * \Brief Returns tab dimention  
+ * \Brief Returns tab dimention
   * \param tab - the tab in the dlg
   * \param dlg - my dialogue
   * \retval int - dimention
@@ -852,6 +852,10 @@ void SMESHGUI_MeshOp::createHypothesis (const int theDim,
                                         const int theType,
                                         const QString& theTypeName)
 {
+  // During a hypothesis creation we might need to select some objects.
+  // Main dialog must not update it's own selected objects in this case.
+  dlg()->deactivateAll();
+
   HypothesisData* aData = SMESH::GetHypothesisData(theTypeName.latin1());
   if (!aData)
     return;
@@ -922,7 +926,7 @@ void SMESHGUI_MeshOp::onEditHyp( const int theHypType, const int theIndex )
 
 //================================================================================
 /*!
- * \brief access to hypothesis data 
+ * \brief access to hypothesis data
   * \param theDim - hyp dimension
   * \param theHypType - hyp type (Algo,MainHyp or AddHyp)
   * \param theIndex - index in the list
@@ -1105,7 +1109,7 @@ void SMESHGUI_MeshOp::onAlgoSelected( const int theIndex,
 
 //================================================================================
 /*!
- * \brief Creates and selects hypothesis of hypotheses set 
+ * \brief Creates and selects hypothesis of hypotheses set
  * \param theSetName - The name of hypotheses set
  */
 //================================================================================
@@ -1201,7 +1205,7 @@ bool SMESHGUI_MeshOp::createMesh( QString& theMess )
 
     for ( int aDim = SMESH::DIM_1D; aDim <= SMESH::DIM_3D; aDim++ ) {
       if ( !isAccessibleDim( aDim )) continue;
-        
+
       // assign hypotheses
       for ( int aHypType = MainHyp; aHypType <= AddHyp; aHypType++ ) {
         int aHypIndex = currentHyp( aDim, aHypType );