diff --git a/src/Mod/Sketcher/Gui/CommandCreateGeo.cpp b/src/Mod/Sketcher/Gui/CommandCreateGeo.cpp
index f7d00610ee..ba1496e225 100644
--- a/src/Mod/Sketcher/Gui/CommandCreateGeo.cpp
+++ b/src/Mod/Sketcher/Gui/CommandCreateGeo.cpp
@@ -555,7 +555,8 @@ public:
                         "conList.append(Sketcher.Constraint('Horizontal',%i))\n"
                         "conList.append(Sketcher.Constraint('Vertical',%i))\n"
                         "conList.append(Sketcher.Constraint('Vertical',%i))\n"
-                        "%s.addConstraint(conList)\n",
+                        "%s.addConstraint(conList)\n"
+                        "del geoList, conList\n",
                         EditCurve[0].x,EditCurve[0].y,EditCurve[1].x,EditCurve[1].y, // line 1
                         EditCurve[1].x,EditCurve[1].y,EditCurve[2].x,EditCurve[2].y, // line 2
                         EditCurve[2].x,EditCurve[2].y,EditCurve[3].x,EditCurve[3].y, // line 3
@@ -594,7 +595,8 @@ public:
                         "conList.append(Sketcher.Constraint('Vertical',%i))\n"
                         "conList.append(Sketcher.Constraint('Vertical',%i))\n"
                         "conList.append(Sketcher.Constraint('Symmetric',%i,2,%i,1,%i,1))\n"
-                        "%s.addConstraint(conList)\n",
+                        "%s.addConstraint(conList)\n"
+                        "del geoList, conList\n",
                         EditCurve[0].x,EditCurve[0].y,EditCurve[1].x,EditCurve[1].y, // line 1
                         EditCurve[1].x,EditCurve[1].y,EditCurve[2].x,EditCurve[2].y, // line 2
                         EditCurve[2].x,EditCurve[2].y,EditCurve[3].x,EditCurve[3].y, // line 3
@@ -930,7 +932,8 @@ public:
                     "conList.append(Sketcher.Constraint('Equal', %i, %i))\n"
                     "conList.append(Sketcher.Constraint('Equal', %i, %i))\n"
                     "conList.append(Sketcher.Constraint('Equal', %i, %i))\n"
-                    "%s.addConstraint(conList)\n",
+                    "%s.addConstraint(conList)\n"
+                    "del geoList, conList\n",
                     StartPos.x + (signX * radius), StartPos.y + (signY * radius), // center of the  arc 1
                     radius,
                     start, end,                 // start and end angle of arc1
@@ -984,7 +987,8 @@ public:
                     "conList.append(Sketcher.Constraint('PointOnObject', %i, 1, %i, ))\n"
                     "conList.append(Sketcher.Constraint('PointOnObject', %i, 1, %i, ))\n"
                     "conList.append(Sketcher.Constraint('PointOnObject', %i, 1, %i, ))\n"
-                    "%s.addConstraint(conList)\n",
+                    "%s.addConstraint(conList)\n"
+                    "del geoList, conList\n",
                     StartPos.x, StartPos.y, // point at StartPos
                     EndPos.x, EndPos.y,     // point at EndPos
                     Gui::Command::getObjectCmd(sketchgui->getObject()).c_str(), // the sketch
@@ -4843,6 +4847,7 @@ public:
                 }
 
                 cstream << Gui::Command::getObjectCmd(sketchgui->getObject()) << ".addConstraint(conList)\n";
+                cstream << "del conList\n";
 
                 Gui::Command::doCommand(Gui::Command::Doc, cstream.str().c_str());
 
@@ -7129,7 +7134,8 @@ public:
                     "conList.append(Sketcher.Constraint('Tangent', %i, 2, %i, 1))\n"
                     "conList.append(Sketcher.Constraint('Tangent', %i, 2, %i, 1))\n"
                     "conList.append(Sketcher.Constraint('Equal', %i, %i))\n"
-                    "%s.addConstraint(conList)\n",
+                    "%s.addConstraint(conList)\n"
+                    "del geoList, conList\n",
                     StartPos.x, StartPos.y,           // center of the arc1
                     r,                                // radius arc1
                     start, end,                       // start and end angle of arc1
diff --git a/src/Mod/Sketcher/Gui/TaskSketcherConstraints.cpp b/src/Mod/Sketcher/Gui/TaskSketcherConstraints.cpp
index acfb48c942..93ec845a5e 100644
--- a/src/Mod/Sketcher/Gui/TaskSketcherConstraints.cpp
+++ b/src/Mod/Sketcher/Gui/TaskSketcherConstraints.cpp
@@ -379,7 +379,7 @@ public:
 class ExpressionDelegate : public QStyledItemDelegate
 {
 public:
-    ExpressionDelegate(QListWidget * _view) : view(_view) { }
+    ExpressionDelegate(QListWidget * _view) : QStyledItemDelegate(_view), view(_view) { }
 protected:
     QPixmap getIcon(const char* name, const QSize& size) const
     {
diff --git a/src/Mod/Sketcher/Gui/ViewProviderSketch.cpp b/src/Mod/Sketcher/Gui/ViewProviderSketch.cpp
index c3a89f5c12..e22254d2af 100644
--- a/src/Mod/Sketcher/Gui/ViewProviderSketch.cpp
+++ b/src/Mod/Sketcher/Gui/ViewProviderSketch.cpp
@@ -6376,6 +6376,7 @@ bool ViewProviderSketch::setEdit(int ModNum)
                         "  tv.sketchClipPlane(ActiveSketch, ActiveSketch.ViewObject.SectionView)\n"
                         "tv.hide(ActiveSketch)\n"
                         "del(tv)\n"
+                        "del(ActiveSketch)\n"
                         ).arg(QString::fromLatin1(getDocument()->getDocument()->getName()),
                               QString::fromLatin1(getSketchObject()->getNameInDocument()),
                               QString::fromLatin1(Gui::Command::getObjectCmd(editObj).c_str()),
@@ -6907,6 +6908,7 @@ void ViewProviderSketch::unsetEdit(int ModNum)
                     "  tv.restore()\n"
                     "ActiveSketch.ViewObject.TempoVis = None\n"
                     "del(tv)\n"
+                    "del(ActiveSketch)\n"
                     ).arg(QString::fromLatin1(getDocument()->getDocument()->getName())).arg(
                           QString::fromLatin1(getSketchObject()->getNameInDocument()));
         QByteArray cmdstr_bytearray = cmdstr.toLatin1();