diff --git a/src/Gui/Document.cpp b/src/Gui/Document.cpp
index 512001d671..ad4ccc5796 100644
--- a/src/Gui/Document.cpp
+++ b/src/Gui/Document.cpp
@@ -1054,9 +1054,9 @@ void Document::createView(const Base::Type& typeId)
 
     std::list<MDIView*> theViews = this->getMDIViewsOfType(typeId);
     if (typeId == View3DInventor::getClassTypeId()) {
-        View3DInventor* firstView = 0;
         View3DInventor* view3D = new View3DInventor(this, getMainWindow());
-        if (firstView) {
+        if (!theViews.empty()) {
+            View3DInventor* firstView = static_cast<View3DInventor*>(theViews.front());
             std::string overrideMode = firstView->getViewer()->getOverrideMode();
             view3D->getViewer()->setOverrideMode(overrideMode);
         }
diff --git a/src/Mod/Part/Gui/TaskAttacher.cpp b/src/Mod/Part/Gui/TaskAttacher.cpp
index cf482671aa..a751027b09 100644
--- a/src/Mod/Part/Gui/TaskAttacher.cpp
+++ b/src/Mod/Part/Gui/TaskAttacher.cpp
@@ -896,7 +896,7 @@ void TaskAttacher::visibilityAutomation(bool opening_not_closing)
 //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 
 TaskDlgAttacher::TaskDlgAttacher(Gui::ViewProviderDocumentObject *ViewProvider, bool createBox)
-    : TaskDialog(),ViewProvider(ViewProvider)
+    : TaskDialog(),ViewProvider(ViewProvider), parameter(nullptr)
 {
     assert(ViewProvider);
     
diff --git a/src/Mod/Sketcher/Gui/CommandConstraints.cpp b/src/Mod/Sketcher/Gui/CommandConstraints.cpp
index e7c3b1bf36..1265b84bc4 100644
--- a/src/Mod/Sketcher/Gui/CommandConstraints.cpp
+++ b/src/Mod/Sketcher/Gui/CommandConstraints.cpp
@@ -798,7 +798,8 @@ namespace SketcherGui {
         App::DocumentObject* object;
     public:
         GenericConstraintSelection(App::DocumentObject* obj)
-            : Gui::SelectionFilterGate((Gui::SelectionFilter*)0), object(obj)
+            : Gui::SelectionFilterGate((Gui::SelectionFilter*)0)
+            , object(obj), allowedSelTypes(0)
         {}
 
         bool allow(App::Document *, App::DocumentObject *pObj, const char *sSubName)
@@ -913,7 +914,7 @@ class DrawSketchHandlerGenConstraint: public DrawSketchHandler
 {
 public:
     DrawSketchHandlerGenConstraint(const char* cursor[], CmdSketcherConstraint *_cmd)
-        : constraintCursor(cursor), cmd(_cmd) {}
+        : constraintCursor(cursor), cmd(_cmd), seqIndex(0) {}
     virtual ~DrawSketchHandlerGenConstraint()
     {
         Gui::Selection().rmvSelectionGate();
@@ -3521,7 +3522,10 @@ void CmdSketcherConstrainPerpendicular::activated(int iMsg)
 
             const Part::Geometry *geo1 = Obj->getGeometry(GeoId1);
             const Part::Geometry *geo2 = Obj->getGeometry(GeoId2);
-            
+            if (!geo1 || !geo2) {
+                return;
+            }
+
             if (geo1->getTypeId() != Part::GeomLineSegment::getClassTypeId() &&
                 geo2->getTypeId() != Part::GeomLineSegment::getClassTypeId()) {
                 QMessageBox::warning(Gui::getMainWindow(), QObject::tr("Wrong selection"),
@@ -3529,9 +3533,8 @@ void CmdSketcherConstrainPerpendicular::activated(int iMsg)
                 return;
             }
             
-            if( geo1 && geo2 &&
-                ( geo1->getTypeId() == Part::GeomBSplineCurve::getClassTypeId() ||
-                  geo2->getTypeId() == Part::GeomBSplineCurve::getClassTypeId() )){
+            if (geo1->getTypeId() == Part::GeomBSplineCurve::getClassTypeId() ||
+                geo2->getTypeId() == Part::GeomBSplineCurve::getClassTypeId()){
                 
                 // unsupported until tangent to BSpline at any point implemented.
                 QMessageBox::warning(Gui::getMainWindow(), QObject::tr("Wrong selection"),
@@ -3546,10 +3549,10 @@ void CmdSketcherConstrainPerpendicular::activated(int iMsg)
             geo1 = Obj->getGeometry(GeoId1);
             geo2 = Obj->getGeometry(GeoId2);
 
-            if( geo1->getTypeId() == Part::GeomEllipse::getClassTypeId() ||
+            if (geo1->getTypeId() == Part::GeomEllipse::getClassTypeId() ||
                 geo1->getTypeId() == Part::GeomArcOfEllipse::getClassTypeId() ||
                 geo1->getTypeId() == Part::GeomArcOfHyperbola::getClassTypeId() ||
-                geo1->getTypeId() == Part::GeomArcOfParabola::getClassTypeId() ) {
+                geo1->getTypeId() == Part::GeomArcOfParabola::getClassTypeId()) {
 
                 Base::Vector3d center;
                 Base::Vector3d majdir;
@@ -3705,6 +3708,9 @@ void CmdSketcherConstrainPerpendicular::applyConstraint(std::vector<SelIdPair> &
 
         const Part::Geometry *geo1 = Obj->getGeometry(GeoId1);
         const Part::Geometry *geo2 = Obj->getGeometry(GeoId2);
+        if (!geo1 || !geo2) {
+            return;
+        }
 
         if (geo1->getTypeId() != Part::GeomLineSegment::getClassTypeId() &&
             geo2->getTypeId() != Part::GeomLineSegment::getClassTypeId()) {
@@ -3713,9 +3719,8 @@ void CmdSketcherConstrainPerpendicular::applyConstraint(std::vector<SelIdPair> &
             return;
         }
 
-        if( geo1 && geo2 &&
-            ( geo1->getTypeId() == Part::GeomBSplineCurve::getClassTypeId() ||
-              geo2->getTypeId() == Part::GeomBSplineCurve::getClassTypeId() )){
+        if (geo1->getTypeId() == Part::GeomBSplineCurve::getClassTypeId() ||
+            geo2->getTypeId() == Part::GeomBSplineCurve::getClassTypeId()){
 
             // unsupported until tangent to BSpline at any point implemented.
             QMessageBox::warning(Gui::getMainWindow(), QObject::tr("Wrong selection"),
diff --git a/src/Mod/Sketcher/Gui/CommandCreateGeo.cpp b/src/Mod/Sketcher/Gui/CommandCreateGeo.cpp
index 5aaa2bd2fc..1833f53314 100644
--- a/src/Mod/Sketcher/Gui/CommandCreateGeo.cpp
+++ b/src/Mod/Sketcher/Gui/CommandCreateGeo.cpp
@@ -3872,6 +3872,10 @@ public:
     DrawSketchHandlerArcOfParabola()
         : Mode(STATUS_SEEK_First)
         , EditCurve(34)
+        , startAngle(0)
+        , endAngle(0)
+        , arcAngle(0)
+        , arcAngle_t(0)
     {
     }
     virtual ~DrawSketchHandlerArcOfParabola(){}
@@ -4150,7 +4154,7 @@ protected:
     SelectMode Mode;
     std::vector<Base::Vector2d> EditCurve;
     Base::Vector2d focusPoint, axisPoint, startingPoint, endPoint;
-    double rx, ry, startAngle, endAngle, arcAngle, arcAngle_t;
+    double startAngle, endAngle, arcAngle, arcAngle_t;
     std::vector<AutoConstraint> sugConstr1, sugConstr2, sugConstr3, sugConstr4;
 };