View does not appear on Redo

Crash in Page on Redo View

src/Mod/TechDraw/App/DrawViewDimension.cpp

@@ -195,7 +195,7 @@ App::DocumentObjectExecReturn *DrawViewDimension::execute(void)
 
     //TODO: if MeasureType = Projected and the Projected shape changes, the Dimension may become invalid (see tilted Cube example)
 
-    return App::DocumentObject::StdReturn;
+    return App::DocumentObject::execute();;
 }
 
 std::string  DrawViewDimension::getFormatedValue() const

src/Mod/TechDraw/App/DrawViewPart.cpp

@@ -114,7 +114,7 @@ DrawViewPart::DrawViewPart(void) : geometryObject(0)
     //ADD_PROPERTY_TYPE(ShowIsoLines ,(false),group,App::Prop_None,"Iso u,v lines on/off");
     ADD_PROPERTY_TYPE(LineWidth,(0.7f),vgroup,App::Prop_None,"The thickness of visible lines");
     ADD_PROPERTY_TYPE(HiddenWidth,(0.15),vgroup,App::Prop_None,"The thickness of hidden lines, if enabled");
-    ADD_PROPERTY_TYPE(Tolerance,(0.05f),vgroup,App::Prop_None,"The tessellation tolerance");
+    ADD_PROPERTY_TYPE(Tolerance,(0.05f),vgroup,App::Prop_None,"The tessellation tolerance");        //tessellation?
     Tolerance.setConstraints(&floatRange);
     ADD_PROPERTY_TYPE(XAxisDirection ,(1,0,0) ,group,App::Prop_None,"Direction to use as X-axis in projection");
 
@@ -189,6 +189,7 @@ short DrawViewPart::mustExecute() const
             ShowSmoothLines.isTouched() ||
             ShowSeamLines.isTouched()   ||
             LineWidth.isTouched()       ||
+            Tolerance.isTouched()       ||
             HiddenWidth.isTouched());
     return result;
 }
@@ -203,7 +204,7 @@ void DrawViewPart::onChanged(const App::Property* prop)
             prop == &ScaleType ||
             prop == &ShowHiddenLines ||
             prop == &ShowSmoothLines ||
-            prop == &ShowSeamLines  ||
+            prop == &ShowSeamLines   ||
             prop == &LineWidth       ||
             prop == &HiddenWidth     ) {
             try {

src/Mod/TechDraw/Gui/MDIViewPage.cpp

@@ -103,7 +103,7 @@ MDIViewPage::MDIViewPage(ViewProviderPage *pageVp, Gui::Document* doc, QWidget*
     m_exportSVGAction = new QAction(tr("&Export SVG"), this);
     connect(m_exportSVGAction, SIGNAL(triggered()), this, SLOT(saveSVG()));
 
-    //m_outlineAction is obs? never set to Enabled?
+    //m_outlineAction is obs? never set to Enabled?
     m_outlineAction = new QAction(tr("&Outline"), this);
     m_outlineAction->setEnabled(false);
     m_outlineAction->setCheckable(true);
@@ -1080,6 +1080,14 @@ void MDIViewPage::selectionChanged()
                   continue;
 
                 TechDraw::DrawView *dimObj = dimItem->getViewObject();
+                if (!dimObj) {
+                    continue;
+                }
+                const char* name = dimObj->getNameInDocument();
+                if (!name) {                                   //can happen during undo/redo if Dim is selected???
+                    //Base::Console().Log("INFO - MDIVP::selectionChanged - dimObj name is null!\n");
+                    continue;
+                }
 
                 //bool accepted =
                 static_cast<void> (Gui::Selection().addSelection(dimObj->getDocument()->getName(),dimObj->getNameInDocument()));

src/Mod/TechDraw/Gui/QGIViewPart.cpp

@@ -123,8 +123,12 @@ void QGIViewPart::tidy()
 
 void QGIViewPart::setViewPartFeature(TechDraw::DrawViewPart *obj)
 {
+    if (!obj)
+        return;
+
     // called from QGVPage
     setViewFeature(static_cast<TechDraw::DrawView *>(obj));
+    draw();
 }
 
 QPainterPath QGIViewPart::drawPainterPath(TechDrawGeometry::BaseGeom *baseGeom) const
@@ -280,6 +284,8 @@ void QGIViewPart::updateView(bool update)
             }
         }
         draw();
+    } else {
+        QGIView::draw();
     }
 }
 

src/Mod/TechDraw/Gui/QGVPage.cpp

@@ -127,6 +127,11 @@ void QGVPage::drawBackground(QPainter *p, const QRectF &)
     if(!drawBkg)
         return;
 
+    if (!pageGui->getPageObject()) {
+        //Base::Console().Log("TROUBLE - QGVP::drawBackground - no Page Object!\n");
+        return;
+    }
+
     p->save();
     p->resetTransform();
 

src/Mod/TechDraw/Gui/ViewProviderPage.cpp

@@ -337,5 +337,10 @@ void ViewProviderPage::finishRestoring()
 
 TechDraw::DrawPage* ViewProviderPage::getPageObject() const
 {
+    //during redo, pcObject can become invalid, but non-zero??
+    if (!pcObject) {
+        Base::Console().Message("TROUBLE - VPP::getPageObject - no Page Object!\n");
+        return nullptr;
+    }
     return dynamic_cast<TechDraw::DrawPage*>(pcObject);
 }