From: nds <nds@opencascade.com>
Date: Sat, 12 Sep 2015 08:40:31 +0000 (+0300)
Subject: Issue #956 Fatal error as result of action without OCC scene
X-Git-Tag: V_1.4.0_beta4~5
X-Git-Url: http://git.salome-platform.org/gitweb/?a=commitdiff_plain;h=6ccac2f149c55637e4ed34b0ac203593ae3b0453;p=modules%2Fshaper.git

Issue #956 Fatal error as result of action without OCC scene
---

diff --git a/src/ModuleBase/ModuleBase_WidgetValidated.cpp b/src/ModuleBase/ModuleBase_WidgetValidated.cpp
index c117e8ed0..55abdb503 100644
--- a/src/ModuleBase/ModuleBase_WidgetValidated.cpp
+++ b/src/ModuleBase/ModuleBase_WidgetValidated.cpp
@@ -109,9 +109,9 @@ bool ModuleBase_WidgetValidated::isValidInFilters(const ModuleBase_ViewerPrs& th
         Handle(SelectMgr_Filter) aFilter = anIt.Value();
         aValid = aFilter->IsOk(anOwner);
       }
-      if (!isActivated)
-        activateFilters(false);
     }
+    if (!isActivated)
+      activateFilters(false);
   }
 
   // removes created owner
diff --git a/src/NewGeom/NewGeom_Module.cpp b/src/NewGeom/NewGeom_Module.cpp
index 17c0574e4..0d2cdaa76 100644
--- a/src/NewGeom/NewGeom_Module.cpp
+++ b/src/NewGeom/NewGeom_Module.cpp
@@ -191,8 +191,11 @@ bool NewGeom_Module::activateModule(SUIT_Study* theStudy)
   aResMgr->setValue("Study", "store_positions", false);
 
   // Synchronize displayed objects
-  if (mySelector && mySelector->viewer()) {
-    Handle(AIS_InteractiveContext) aContext = mySelector->viewer()->getAISContext();
+  Handle(AIS_InteractiveContext) aContext;
+  if (mySelector && mySelector->viewer())
+    aContext = mySelector->viewer()->getAISContext();
+
+  if (!aContext.IsNull()) {
     XGUI_Displayer* aDisp = myWorkshop->displayer();
     QObjectPtrList aObjList = aDisp->displayedObjects();
 
diff --git a/src/PartSet/PartSet_Module.cpp b/src/PartSet/PartSet_Module.cpp
index 9cb9af831..5713d7dec 100755
--- a/src/PartSet/PartSet_Module.cpp
+++ b/src/PartSet/PartSet_Module.cpp
@@ -801,17 +801,16 @@ void PartSet_Module::onViewTransformed(int theTrsfType)
   // if the operation is panning or rotate or panglobal then do nothing
   if ((theTrsfType == 1) || (theTrsfType == 3) || (theTrsfType == 4))
     return;
-
   ModuleBase_IViewer* aViewer = myWorkshop->viewer();
+  Handle(AIS_InteractiveContext) aContext = aViewer->AISContext();
+  if (aContext.IsNull())
+    return;
+
   //Handle(V3d_View) aView = aViewer->activeView();
 
   XGUI_ModuleConnector* aConnector = dynamic_cast<XGUI_ModuleConnector*>(myWorkshop);
   XGUI_Workshop* aWorkshop = aConnector->workshop();
   XGUI_Displayer* aDisplayer = aWorkshop->displayer();
-  Handle(AIS_InteractiveContext) aContext = aViewer->AISContext();
-  if (aContext.IsNull())
-    return;
-
   Handle(V3d_Viewer) aV3dViewer = aContext->CurrentViewer();
   Handle(V3d_View) aView;
   double aScale = 0;
@@ -1068,7 +1067,11 @@ void PartSet_Module::onViewCreated(ModuleBase_IViewWindow*)
 {
   // z layer is created for all started operations in order to visualize operation AIS presentation
   // over the object
-  Handle(V3d_Viewer) aViewer = myWorkshop->viewer()->AISContext()->CurrentViewer();
+  Handle(AIS_InteractiveContext) aContext = myWorkshop->viewer()->AISContext();
+  if (aContext.IsNull())
+    return;
+
+  Handle(V3d_Viewer) aViewer = aContext->CurrentViewer();
   if (myVisualLayerId == 0) {
     if (myVisualLayerId == 0)
       aViewer->AddZLayer(myVisualLayerId);
diff --git a/src/PartSet/PartSet_SketcherMgr.cpp b/src/PartSet/PartSet_SketcherMgr.cpp
index 4a84b0cc1..9bccd1ab0 100644
--- a/src/PartSet/PartSet_SketcherMgr.cpp
+++ b/src/PartSet/PartSet_SketcherMgr.cpp
@@ -373,11 +373,10 @@ void PartSet_SketcherMgr::onMousePressed(ModuleBase_IViewWindow* theWnd, QMouseE
       return;
 
     Handle(AIS_InteractiveContext) aContext = aViewer->AISContext();
-    if (aContext.IsNull())
-      return;
-    // MoveTo in order to highlight current object
-    aContext->MoveTo(theEvent->x(), theEvent->y(), theWnd->v3dView());
-
+    if (!aContext.IsNull()) {
+      // MoveTo in order to highlight current object
+      aContext->MoveTo(theEvent->x(), theEvent->y(), theWnd->v3dView());
+    }
     // Remember highlighted objects for editing
     ModuleBase_ISelection* aSelect = aWorkshop->selection();
 
@@ -1100,36 +1099,36 @@ void PartSet_SketcherMgr::getCurrentSelection(const FeaturePtr& theFeature,
 
   ModuleBase_IViewer* aViewer = theWorkshop->viewer();
   Handle(AIS_InteractiveContext) aContext = aViewer->AISContext();
-  if (aContext.IsNull())
-    return;
-  XGUI_ModuleConnector* aConnector = dynamic_cast<XGUI_ModuleConnector*>(theWorkshop);
-  XGUI_Displayer* aDisplayer = aConnector->workshop()->displayer();
+  if (!aContext.IsNull()) {
+    XGUI_ModuleConnector* aConnector = dynamic_cast<XGUI_ModuleConnector*>(theWorkshop);
+    XGUI_Displayer* aDisplayer = aConnector->workshop()->displayer();
 
-  std::list<ResultPtr> aResults = theFeature->results();
-  std::list<ResultPtr>::const_iterator aIt;
-  for (aIt = aResults.begin(); aIt != aResults.end(); ++aIt)
-  {
-    ResultPtr aResult = *aIt;
-    AISObjectPtr aAISObj = aDisplayer->getAISObject(aResult);
-    if (aAISObj.get() == NULL)
-      continue;
-    Handle(AIS_InteractiveObject) anAISIO = aAISObj->impl<Handle(AIS_InteractiveObject)>();
-    for (aContext->InitSelected(); aContext->MoreSelected(); aContext->NextSelected())
+    std::list<ResultPtr> aResults = theFeature->results();
+    std::list<ResultPtr>::const_iterator aIt;
+    for (aIt = aResults.begin(); aIt != aResults.end(); ++aIt)
     {
-      Handle(SelectMgr_EntityOwner) anOwner = aContext->SelectedOwner();
-      if (anOwner->Selectable() != anAISIO)
-        continue;
-      getAttributesOrResults(anOwner, theFeature, theSketch, aResult,
-                             aSelectedAttributes, aSelectedResults);
-    }
-    for (aContext->InitDetected(); aContext->MoreDetected(); aContext->NextDetected()) {
-      Handle(SelectMgr_EntityOwner) anOwner = aContext->DetectedOwner();
-      if (anOwner.IsNull())
+      ResultPtr aResult = *aIt;
+      AISObjectPtr aAISObj = aDisplayer->getAISObject(aResult);
+      if (aAISObj.get() == NULL)
         continue;
-      if (anOwner->Selectable() != anAISIO)
-        continue;
-      getAttributesOrResults(anOwner, theFeature, theSketch, aResult,
-                             aSelectedAttributes, aSelectedResults);
+      Handle(AIS_InteractiveObject) anAISIO = aAISObj->impl<Handle(AIS_InteractiveObject)>();
+      for (aContext->InitSelected(); aContext->MoreSelected(); aContext->NextSelected())
+      {
+        Handle(SelectMgr_EntityOwner) anOwner = aContext->SelectedOwner();
+        if (anOwner->Selectable() != anAISIO)
+          continue;
+        getAttributesOrResults(anOwner, theFeature, theSketch, aResult,
+                               aSelectedAttributes, aSelectedResults);
+      }
+      for (aContext->InitDetected(); aContext->MoreDetected(); aContext->NextDetected()) {
+        Handle(SelectMgr_EntityOwner) anOwner = aContext->DetectedOwner();
+        if (anOwner.IsNull())
+          continue;
+        if (anOwner->Selectable() != anAISIO)
+          continue;
+        getAttributesOrResults(anOwner, theFeature, theSketch, aResult,
+                               aSelectedAttributes, aSelectedResults);
+      }
     }
   }
   theSelection[theFeature] = std::make_pair(aSelectedAttributes, aSelectedResults);
@@ -1139,7 +1138,7 @@ void PartSet_SketcherMgr::getSelectionOwners(const FeaturePtr& theFeature,
                                              const FeaturePtr& theSketch,
                                              ModuleBase_IWorkshop* theWorkshop,
                                              const FeatureToSelectionMap& theSelection,
-                                             SelectMgr_IndexedMapOfOwner& anOwnersToSelect)
+                                             SelectMgr_IndexedMapOfOwner& theOwnersToSelect)
 {
   if (theFeature.get() == NULL)
     return;
@@ -1149,9 +1148,6 @@ void PartSet_SketcherMgr::getSelectionOwners(const FeaturePtr& theFeature,
   std::set<ResultPtr> aSelectedResults = anIt.value().second;
 
   ModuleBase_IViewer* aViewer = theWorkshop->viewer();
-  Handle(AIS_InteractiveContext) aContext = aViewer->AISContext();
-  if (aContext.IsNull())
-    return;
 
   XGUI_ModuleConnector* aConnector = dynamic_cast<XGUI_ModuleConnector*>(theWorkshop);
   XGUI_Displayer* aDisplayer = aConnector->workshop()->displayer();
@@ -1166,7 +1162,7 @@ void PartSet_SketcherMgr::getSelectionOwners(const FeaturePtr& theFeature,
     for  (Standard_Integer i = 1, n = aSelectedOwners.Extent(); i <= n; i++) {
       Handle(SelectMgr_EntityOwner) anOwner = aSelectedOwners(i);
       if (!anOwner.IsNull())
-        anOwnersToSelect.Add(anOwner);
+        theOwnersToSelect.Add(anOwner);
     }
   }
 
@@ -1193,14 +1189,14 @@ void PartSet_SketcherMgr::getSelectionOwners(const FeaturePtr& theFeature,
         AttributePtr aPntAttr = PartSet_Tools::findAttributeBy2dPoint(theFeature, aShape, theSketch);
         if (aPntAttr.get() != NULL &&
             aSelectedAttributes.find(aPntAttr) != aSelectedAttributes.end()) {
-          anOwnersToSelect.Add(anOwner);
+          theOwnersToSelect.Add(anOwner);
         }
       }
       else if (aShapeType == TopAbs_EDGE) {
         bool aFound = aSelectedResults.find(aResult) != aSelectedResults.end();
         if (aSelectedResults.find(aResult) != aSelectedResults.end() &&
-            anOwnersToSelect.FindIndex(anOwner) <= 0)
-          anOwnersToSelect.Add(anOwner);
+            theOwnersToSelect.FindIndex(anOwner) <= 0)
+          theOwnersToSelect.Add(anOwner);
       }
     }
   }
diff --git a/src/XGUI/XGUI_Displayer.cpp b/src/XGUI/XGUI_Displayer.cpp
index 3ee0ccdaa..344704de0 100644
--- a/src/XGUI/XGUI_Displayer.cpp
+++ b/src/XGUI/XGUI_Displayer.cpp
@@ -237,6 +237,7 @@ bool XGUI_Displayer::erase(ObjectPtr theObject, const bool theUpdateViewer)
   Handle(AIS_InteractiveContext) aContext = AISContext();
   if (aContext.IsNull())
     return aErased;
+
   AISObjectPtr anObject = myResult2AISObjectMap[theObject];
   if (anObject) {
     Handle(AIS_InteractiveObject) anAIS = anObject->impl<Handle(AIS_InteractiveObject)>();
@@ -280,7 +281,7 @@ bool XGUI_Displayer::redisplay(ObjectPtr theObject, bool theUpdateViewer)
   }
 
   Handle(AIS_InteractiveContext) aContext = AISContext();
-  if (!aAISIO.IsNull() && !aContext.IsNull()) {
+  if (!aContext.IsNull() && !aAISIO.IsNull()) {
     // Check that the visualized shape is the same and the redisplay is not necessary
     // Redisplay of AIS object leads to this object selection compute and the selection 
     // in the browser is lost
@@ -342,11 +343,8 @@ void XGUI_Displayer::deactivate(ObjectPtr theObject, const bool theUpdateViewer)
     arg(anInfoStr).
     toStdString().c_str());
 #endif
-  if (isVisible(theObject)) {
-    Handle(AIS_InteractiveContext) aContext = AISContext();
-    if (aContext.IsNull())
-      return;
-
+  Handle(AIS_InteractiveContext) aContext = AISContext();
+  if (!aContext.IsNull() && isVisible(theObject)) {
     AISObjectPtr anObj = myResult2AISObjectMap[theObject];
     Handle(AIS_InteractiveObject) anAIS = anObj->impl<Handle(AIS_InteractiveObject)>();
 
@@ -371,11 +369,8 @@ void XGUI_Displayer::deactivateObjects(const QObjectPtrList& theObjList,
 
 void XGUI_Displayer::getModesOfActivation(ObjectPtr theObject, QIntList& theModes)
 {
-  if (!isVisible(theObject))
-    return;
-
   Handle(AIS_InteractiveContext) aContext = AISContext();
-  if (aContext.IsNull())
+  if (aContext.IsNull() || !isVisible(theObject))
     return;
 
   AISObjectPtr aAISObj = getAISObject(theObject);
@@ -425,10 +420,8 @@ void XGUI_Displayer::activateObjects(const QIntList& theModes, const QObjectPtrL
   }
   myActiveSelectionModes = aNewModes;
   Handle(AIS_InteractiveContext) aContext = AISContext();
-  if (aContext.IsNull())
-    return;
   // Open local context if there is no one
-  if (!aContext->HasOpenedContext()) 
+  if (aContext.IsNull() || !aContext->HasOpenedContext()) 
     return;
 
   //aContext->UseDisplayedObjects();
@@ -457,9 +450,7 @@ void XGUI_Displayer::activateObjects(const QIntList& theModes, const QObjectPtrL
 bool XGUI_Displayer::isActive(ObjectPtr theObject) const
 {
   Handle(AIS_InteractiveContext) aContext = AISContext();
-  if (aContext.IsNull())
-    return false;
-  if (!isVisible(theObject))
+  if (aContext.IsNull() || !isVisible(theObject))
     return false;
     
   AISObjectPtr anObj = myResult2AISObjectMap[theObject];
@@ -519,7 +510,7 @@ void XGUI_Displayer::setSelected(const  QList<ModuleBase_ViewerPrs>& theValues,
 void XGUI_Displayer::clearSelected()
 {
   Handle(AIS_InteractiveContext) aContext = AISContext();
-  if (aContext) {
+  if (!aContext.IsNull()) {
     aContext->UnhilightCurrents(false);
     aContext->ClearSelected();
   }
@@ -554,14 +545,15 @@ bool XGUI_Displayer::eraseAll(const bool theUpdateViewer)
 void XGUI_Displayer::deactivateTrihedron() const
 {
   Handle(AIS_InteractiveContext) aContext = myWorkshop->viewer()->AISContext();
-
-  AIS_ListOfInteractive aList;
-  aContext->DisplayedObjects(aList, true);
-  AIS_ListIteratorOfListOfInteractive aIt;
-  for (aIt.Initialize(aList); aIt.More(); aIt.Next()) {
-    Handle(AIS_Trihedron) aTrihedron = Handle(AIS_Trihedron)::DownCast(aIt.Value());
-    if (!aTrihedron.IsNull()) {
-      aContext->Deactivate(aTrihedron);
+  if (!aContext.IsNull()) {
+    AIS_ListOfInteractive aList;
+    aContext->DisplayedObjects(aList, true);
+    AIS_ListIteratorOfListOfInteractive aIt;
+    for (aIt.Initialize(aList); aIt.More(); aIt.Next()) {
+      Handle(AIS_Trihedron) aTrihedron = Handle(AIS_Trihedron)::DownCast(aIt.Value());
+      if (!aTrihedron.IsNull()) {
+        aContext->Deactivate(aTrihedron);
+      }
     }
   }
 }
@@ -569,10 +561,8 @@ void XGUI_Displayer::deactivateTrihedron() const
 void XGUI_Displayer::openLocalContext()
 {
   Handle(AIS_InteractiveContext) aContext = myWorkshop->viewer()->AISContext();
-  if (aContext.IsNull())
-    return;
   // Open local context if there is no one
-  if (!aContext->HasOpenedContext()) {
+  if (!aContext.IsNull() && !aContext->HasOpenedContext()) {
     // Preserve selected objects
     //AIS_ListOfInteractive aAisList;
     //for (aContext->InitCurrent(); aContext->MoreCurrent(); aContext->NextCurrent())
@@ -608,7 +598,7 @@ void XGUI_Displayer::openLocalContext()
 void XGUI_Displayer::closeLocalContexts(const bool theUpdateViewer)
 {
   Handle(AIS_InteractiveContext) aContext = AISContext();
-  if ( (!aContext.IsNull()) && (aContext->HasOpenedContext()) ) {
+  if (!aContext.IsNull() && aContext->HasOpenedContext()) {
     // Preserve selected objects
     //AIS_ListOfInteractive aAisList;
     //for (aContext->InitSelected(); aContext->MoreSelected(); aContext->NextSelected())
@@ -712,34 +702,38 @@ void XGUI_Displayer::activateAIS(const Handle(AIS_InteractiveObject)& theIO,
                                  const int theMode, const bool theUpdateViewer) const
 {
   Handle(AIS_InteractiveContext) aContext = myWorkshop->viewer()->AISContext();
-  aContext->Activate(theIO, theMode, theUpdateViewer);
+  if (!aContext.IsNull()) {
+    aContext->Activate(theIO, theMode, theUpdateViewer);
 
 #ifdef DEBUG_ACTIVATE_AIS
-  ObjectPtr anObject = getObject(theIO);
-  anInfo.append(ModuleBase_Tools::objectInfo((*anIt)));
-  qDebug(QString("activateAIS: theMode = %1, object = %2").arg(theMode).arg(anInfo).toStdString().c_str());
+    ObjectPtr anObject = getObject(theIO);
+    anInfo.append(ModuleBase_Tools::objectInfo((*anIt)));
+    qDebug(QString("activateAIS: theMode = %1, object = %2").arg(theMode).arg(anInfo).toStdString().c_str());
 #endif
+  }
 }
 
 void XGUI_Displayer::deactivateAIS(const Handle(AIS_InteractiveObject)& theIO, const int theMode) const
 {
   Handle(AIS_InteractiveContext) aContext = myWorkshop->viewer()->AISContext();
-  if (theMode == -1)
-    aContext->Deactivate(theIO);
-  else
-    aContext->Deactivate(theIO, theMode);
+  if (!aContext.IsNull()) {
+    if (theMode == -1)
+      aContext->Deactivate(theIO);
+    else
+      aContext->Deactivate(theIO, theMode);
 
 #ifdef DEBUG_DEACTIVATE_AIS
-  ObjectPtr anObject = getObject(theIO);
-  anInfo.append(ModuleBase_Tools::objectInfo((*anIt)));
-  qDebug(QString("deactivateAIS: theMode = %1, object = %2").arg(theMode).arg(anInfo).toStdString().c_str());
+    ObjectPtr anObject = getObject(theIO);
+    anInfo.append(ModuleBase_Tools::objectInfo((*anIt)));
+    qDebug(QString("deactivateAIS: theMode = %1, object = %2").arg(theMode).arg(anInfo).toStdString().c_str());
 #endif
+  }
 }
 
 Handle(AIS_InteractiveContext) XGUI_Displayer::AISContext() const
 {
   Handle(AIS_InteractiveContext) aContext = myWorkshop->viewer()->AISContext();
-  if ((!aContext.IsNull()) && (!aContext->HasOpenedContext())) {
+  if (!aContext.IsNull() && !aContext->HasOpenedContext()) {
     aContext->OpenLocalContext();
     deactivateTrihedron();
     aContext->DefaultDrawer()->VIsoAspect()->SetNumber(0);
@@ -751,7 +745,7 @@ Handle(AIS_InteractiveContext) XGUI_Displayer::AISContext() const
 Handle(SelectMgr_AndFilter) XGUI_Displayer::GetFilter()
 {
   Handle(AIS_InteractiveContext) aContext = AISContext();
-  if (myAndFilter.IsNull() && !aContext.IsNull()) {
+  if (!aContext.IsNull() && myAndFilter.IsNull()) {
     myAndFilter = new SelectMgr_AndFilter();
     aContext->AddFilter(myAndFilter);
   }
@@ -763,10 +757,8 @@ bool XGUI_Displayer::displayAIS(AISObjectPtr theAIS, const bool toActivateInSele
 {
   bool aDisplayed = false;
   Handle(AIS_InteractiveContext) aContext = AISContext();
-  if (aContext.IsNull())
-    return aDisplayed;
   Handle(AIS_InteractiveObject) anAISIO = theAIS->impl<Handle(AIS_InteractiveObject)>();
-  if (!anAISIO.IsNull()) {
+  if (!aContext.IsNull() && !anAISIO.IsNull()) {
     aContext->Display(anAISIO, 0/*wireframe*/, 0, theUpdateViewer, true, AIS_DS_Displayed);
     aDisplayed = true;
     aContext->Deactivate(anAISIO);
@@ -790,12 +782,12 @@ bool XGUI_Displayer::eraseAIS(AISObjectPtr theAIS, const bool theUpdateViewer)
 {
   bool aErased = false;
   Handle(AIS_InteractiveContext) aContext = AISContext();
-  if (aContext.IsNull())
-    return aErased;
-  Handle(AIS_InteractiveObject) anAISIO = theAIS->impl<Handle(AIS_InteractiveObject)>();
-  if (!anAISIO.IsNull() && aContext->IsDisplayed(anAISIO)) {
-    aContext->Remove(anAISIO, theUpdateViewer);
-    aErased = true;
+  if (!aContext.IsNull()) {
+    Handle(AIS_InteractiveObject) anAISIO = theAIS->impl<Handle(AIS_InteractiveObject)>();
+    if (!anAISIO.IsNull() && aContext->IsDisplayed(anAISIO)) {
+      aContext->Remove(anAISIO, theUpdateViewer);
+      aErased = true;
+    }
   }
   return aErased;
 }
@@ -838,7 +830,7 @@ XGUI_Displayer::DisplayMode XGUI_Displayer::displayMode(ObjectPtr theObject) con
 void XGUI_Displayer::deactivateSelectionFilters()
 {
   Handle(AIS_InteractiveContext) aContext = AISContext();
-  if (!myAndFilter.IsNull() && !aContext.IsNull()) {
+  if (!aContext.IsNull() && !myAndFilter.IsNull()) {
     bool aFound = false;
     const SelectMgr_ListOfFilter& aFilters = aContext->Filters();
     SelectMgr_ListIteratorOfListOfFilter anIt(aFilters);
@@ -859,12 +851,14 @@ void XGUI_Displayer::addSelectionFilter(const Handle(SelectMgr_Filter)& theFilte
   if (aContext.IsNull() || hasSelectionFilter(theFilter))
     return;
 
-  Handle(SelectMgr_CompositionFilter) aCompFilter = GetFilter();
-  aCompFilter->Add(theFilter);
+  Handle(SelectMgr_CompositionFilter) aCompositeFilter = GetFilter();
+  if (!aCompositeFilter.IsNull()) {
+    aCompositeFilter->Add(theFilter);
 #ifdef DEBUG_SELECTION_FILTERS
-  int aCount = GetFilter()->StoredFilters().Extent();
-  qDebug(QString("addSelectionFilter: filters.count() = %1").arg(aCount).toStdString().c_str());
+    int aCount = aCompositeFilter->StoredFilters().Extent();
+    qDebug(QString("addSelectionFilter: filters.count() = %1").arg(aCount).toStdString().c_str());
 #endif
+  }
 }
 
 void XGUI_Displayer::removeSelectionFilter(const Handle(SelectMgr_Filter)& theFilter)
@@ -872,13 +866,15 @@ void XGUI_Displayer::removeSelectionFilter(const Handle(SelectMgr_Filter)& theFi
   Handle(AIS_InteractiveContext) aContext = AISContext();
   if (aContext.IsNull())
     return;
+
   Handle(SelectMgr_AndFilter) aCompositeFilter = GetFilter();
-  if (aCompositeFilter->IsIn(theFilter))
+  if (!aCompositeFilter.IsNull() && aCompositeFilter->IsIn(theFilter)) {
     aCompositeFilter->Remove(theFilter);
 #ifdef DEBUG_SELECTION_FILTERS
-  int aCount = GetFilter()->StoredFilters().Extent();
-  qDebug(QString("removeSelectionFilter: filters.count() = %1").arg(aCount).toStdString().c_str());
+    int aCount = aCompositeFilter->StoredFilters().Extent();
+    qDebug(QString("removeSelectionFilter: filters.count() = %1").arg(aCount).toStdString().c_str());
 #endif
+  }
 }
 
 bool XGUI_Displayer::hasSelectionFilter(const Handle(SelectMgr_Filter)& theFilter)
@@ -894,11 +890,13 @@ bool XGUI_Displayer::hasSelectionFilter(const Handle(SelectMgr_Filter)& theFilte
     if (theFilter.Access() == aIt.Value().Access())
       aFilterFound = true;
   }
-  Handle(SelectMgr_CompositionFilter) aCompFilter = GetFilter();
-  const SelectMgr_ListOfFilter& aStoredFilters = aCompFilter->StoredFilters();
-  for (aIt.Initialize(aStoredFilters); aIt.More() && !aFilterFound; aIt.Next()) {
-    if (theFilter.Access() == aIt.Value().Access())
-      aFilterFound = true;
+  Handle(SelectMgr_CompositionFilter) aCompositeFilter = GetFilter();
+  if (!aCompositeFilter.IsNull()) {
+    const SelectMgr_ListOfFilter& aStoredFilters = aCompositeFilter->StoredFilters();
+    for (aIt.Initialize(aStoredFilters); aIt.More() && !aFilterFound; aIt.Next()) {
+      if (theFilter.Access() == aIt.Value().Access())
+        aFilterFound = true;
+    }
   }
   return aFilterFound;
 }
@@ -908,7 +906,10 @@ void XGUI_Displayer::removeFilters()
   Handle(AIS_InteractiveContext) aContext = AISContext();
   if (aContext.IsNull())
     return;
-  GetFilter()->Clear();
+
+  Handle(SelectMgr_CompositionFilter) aCompositeFilter = GetFilter();
+  if (!aCompositeFilter.IsNull())
+    aCompositeFilter->Clear();
 }
 
 void XGUI_Displayer::showOnly(const QObjectPtrList& theList)
diff --git a/src/XGUI/XGUI_Selection.cpp b/src/XGUI/XGUI_Selection.cpp
index a8cd9cc3b..edc113683 100644
--- a/src/XGUI/XGUI_Selection.cpp
+++ b/src/XGUI/XGUI_Selection.cpp
@@ -64,10 +64,7 @@ Handle(AIS_InteractiveObject) XGUI_Selection::getIO(const ModuleBase_ViewerPrs&
 void XGUI_Selection::getSelectedInViewer(QList<ModuleBase_ViewerPrs>& thePresentations) const
 {
   Handle(AIS_InteractiveContext) aContext = myWorkshop->viewer()->AISContext();
-  if (aContext.IsNull())
-    return;
-
-  if (aContext->HasOpenedContext()) {
+  if (!aContext.IsNull() && aContext->HasOpenedContext()) {
     QList<long> aSelectedIds; // Remember of selected address in order to avoid duplicates
     for (aContext->InitSelected(); aContext->MoreSelected(); aContext->NextSelected()) {
       ModuleBase_ViewerPrs aPrs;
@@ -132,11 +129,13 @@ void XGUI_Selection::fillPresentation(ModuleBase_ViewerPrs& thePrs,
 
 QList<ModuleBase_ViewerPrs> XGUI_Selection::getHighlighted() const
 {
-  QList<long> aSelectedIds; // Remember of selected address in order to avoid duplicates
   QList<ModuleBase_ViewerPrs> aPresentations;
-  XGUI_Displayer* aDisplayer = myWorkshop->displayer();
-
   Handle(AIS_InteractiveContext) aContext = myWorkshop->viewer()->AISContext();
+  if (aContext.IsNull())
+    return aPresentations;
+
+  QList<long> aSelectedIds; // Remember of selected address in order to avoid duplicates
+  XGUI_Displayer* aDisplayer = myWorkshop->displayer();
   for (aContext->InitDetected(); aContext->MoreDetected(); aContext->NextDetected()) {
     ModuleBase_ViewerPrs aPrs;
     Handle(AIS_InteractiveObject) anIO = aContext->DetectedInteractive();
@@ -195,10 +194,13 @@ QModelIndexList XGUI_Selection::selectedIndexes() const
 //**************************************************************
 void XGUI_Selection::selectedAISObjects(AIS_ListOfInteractive& theList) const
 {
-  Handle(AIS_InteractiveContext) aContext = myWorkshop->viewer()->AISContext();
   theList.Clear();
-  for (aContext->InitSelected(); aContext->MoreSelected(); aContext->NextSelected())
-    theList.Append(aContext->SelectedInteractive());
+
+  Handle(AIS_InteractiveContext) aContext = myWorkshop->viewer()->AISContext();
+  if (!aContext.IsNull()) {
+    for (aContext->InitSelected(); aContext->MoreSelected(); aContext->NextSelected())
+      theList.Append(aContext->SelectedInteractive());
+  }
 }
 
 //**************************************************************
@@ -221,6 +223,9 @@ void XGUI_Selection::selectedShapes(NCollection_List<TopoDS_Shape>& theList,
 {
   theList.Clear();
   Handle(AIS_InteractiveContext) aContext = myWorkshop->viewer()->AISContext();
+  if (aContext.IsNull())
+    return;
+
   for (aContext->InitSelected(); aContext->MoreSelected(); aContext->NextSelected()) {
     TopoDS_Shape aShape = aContext->SelectedShape();
     if (!aShape.IsNull()) {
@@ -240,9 +245,10 @@ void XGUI_Selection::selectedShapes(NCollection_List<TopoDS_Shape>& theList,
 void XGUI_Selection::selectedOwners(SelectMgr_IndexedMapOfOwner& theSelectedOwners) const
 {
   Handle(AIS_InteractiveContext) aContext = myWorkshop->viewer()->AISContext();
-
-  for (aContext->InitSelected(); aContext->MoreSelected(); aContext->NextSelected()) {
-    theSelectedOwners.Add(aContext->SelectedOwner());
+  if (!aContext.IsNull()) {
+    for (aContext->InitSelected(); aContext->MoreSelected(); aContext->NextSelected()) {
+      theSelectedOwners.Add(aContext->SelectedOwner());
+    }
   }
 }
 
@@ -251,8 +257,7 @@ void XGUI_Selection::entityOwners(const Handle(AIS_InteractiveObject)& theObject
                                   SelectMgr_IndexedMapOfOwner& theOwners) const
 {
   Handle(AIS_InteractiveContext) aContext = myWorkshop->viewer()->AISContext();
-
-  if (theObject.IsNull() || aContext.IsNull())
+  if (aContext.IsNull() || theObject.IsNull())
     return;
 
   TColStd_ListOfInteger aModes;
diff --git a/src/XGUI/XGUI_SelectionMgr.cpp b/src/XGUI/XGUI_SelectionMgr.cpp
index 05c86e20e..3a13e3213 100644
--- a/src/XGUI/XGUI_SelectionMgr.cpp
+++ b/src/XGUI/XGUI_SelectionMgr.cpp
@@ -50,12 +50,14 @@ void XGUI_SelectionMgr::setSelectedOwners(const SelectMgr_IndexedMapOfOwner& the
   selection()->selectedOwners(aSelectedOwners);
 
   Handle(AIS_InteractiveContext) aContext = myWorkshop->viewer()->AISContext();
-  for  (Standard_Integer i = 1, n = theSelectedOwners.Extent(); i <= n; i++)  {
-    Handle(SelectMgr_EntityOwner) anOwner = theSelectedOwners(i);
-    if (aSelectedOwners.FindIndex(anOwner) > 0)
-      continue;
+  if (!aContext.IsNull()) {
+    for  (Standard_Integer i = 1, n = theSelectedOwners.Extent(); i <= n; i++)  {
+      Handle(SelectMgr_EntityOwner) anOwner = theSelectedOwners(i);
+      if (aSelectedOwners.FindIndex(anOwner) > 0)
+        continue;
 
-    aContext->AddOrRemoveSelected(anOwner, isUpdateViewer);
+      aContext->AddOrRemoveSelected(anOwner, isUpdateViewer);
+    }
   }
 }
 
@@ -63,6 +65,9 @@ void XGUI_SelectionMgr::setSelectedOwners(const SelectMgr_IndexedMapOfOwner& the
 void XGUI_SelectionMgr::updateSelectedOwners(bool isUpdateViewer)
 {
   Handle(AIS_InteractiveContext) aContext = myWorkshop->viewer()->AISContext();
+  if (aContext.IsNull())
+    return;
+
   const SelectMgr_ListOfFilter& aFilters = aContext->Filters();
 
   SelectMgr_IndexedMapOfOwner anOwnersToDeselect;
@@ -99,11 +104,13 @@ void XGUI_SelectionMgr::onViewerSelection()
 {
   QObjectPtrList aFeatures;
   Handle(AIS_InteractiveContext) aContext = myWorkshop->viewer()->AISContext();
-  for (aContext->InitSelected(); aContext->MoreSelected(); aContext->NextSelected()) {
-    Handle(AIS_InteractiveObject) anIO = aContext->SelectedInteractive();
-    ObjectPtr aResult = myWorkshop->displayer()->getObject(anIO);
-    if (aResult)
-      aFeatures.append(aResult);
+  if (!aContext.IsNull()) {
+    for (aContext->InitSelected(); aContext->MoreSelected(); aContext->NextSelected()) {
+      Handle(AIS_InteractiveObject) anIO = aContext->SelectedInteractive();
+      ObjectPtr aResult = myWorkshop->displayer()->getObject(anIO);
+      if (aResult)
+        aFeatures.append(aResult);
+    }
   }
   bool aBlocked = myWorkshop->objectBrowser()->blockSignals(true);
   myWorkshop->objectBrowser()->setObjectsSelected(aFeatures);