diff --git a/src/Mod/TechDraw/App/Geometry.cpp b/src/Mod/TechDraw/App/Geometry.cpp
index 54ae761456..b81e6741e0 100644
--- a/src/Mod/TechDraw/App/Geometry.cpp
+++ b/src/Mod/TechDraw/App/Geometry.cpp
@@ -182,6 +182,7 @@ BaseGeom::BaseGeom() :
 {
     occEdge = TopoDS_Edge();
     cosmeticTag = std::string();
+    tag = boost::uuids::nil_uuid();
 }
 
 BaseGeomPtr BaseGeom::copy()
diff --git a/src/Mod/TechDraw/Gui/CommandExtensionDims.cpp b/src/Mod/TechDraw/Gui/CommandExtensionDims.cpp
index f17658bb5e..f97a2535d2 100644
--- a/src/Mod/TechDraw/Gui/CommandExtensionDims.cpp
+++ b/src/Mod/TechDraw/Gui/CommandExtensionDims.cpp
@@ -105,7 +105,7 @@ void execInsertPrefixChar(Gui::Command* cmd, std::string prefixChar) {
         for (auto selected : selection) {
             auto object = selected.getObject();
             if (object->isDerivedFrom(TechDraw::DrawViewDimension::getClassTypeId())) {
-                auto dim = dynamic_cast<TechDraw::DrawViewDimension*>(selected.getObject());
+                auto dim = static_cast<TechDraw::DrawViewDimension*>(selected.getObject());
                 std::string formatSpec = dim->FormatSpec.getStrValue();
                 formatSpec = prefixChar + formatSpec;
                 dim->FormatSpec.setValue(formatSpec);
@@ -190,7 +190,7 @@ void execRemovePrefixChar(Gui::Command* cmd) {
         {
             auto object = selected.getObject();
             if (object->isDerivedFrom(TechDraw::DrawViewDimension::getClassTypeId())) {
-                auto dim = dynamic_cast<TechDraw::DrawViewDimension*>(selected.getObject());
+                auto dim = static_cast<TechDraw::DrawViewDimension*>(selected.getObject());
                 std::string formatSpec = dim->FormatSpec.getStrValue();
                 int pos = formatSpec.find("%.");
                 if (pos != 0)
@@ -360,7 +360,7 @@ void execIncreaseDecreaseDecimal(Gui::Command* cmd, int delta) {
         for (auto selected : selection) {
             auto object = selected.getObject();
             if (object->isDerivedFrom(TechDraw::DrawViewDimension::getClassTypeId())) {
-                auto dim = dynamic_cast<TechDraw::DrawViewDimension*>(selected.getObject());
+                auto dim = static_cast<TechDraw::DrawViewDimension*>(selected.getObject());
                 std::string formatSpec = dim->FormatSpec.getStrValue();
                 std::string searchStr("%.");
                 int numFound = formatSpec.find(searchStr) + 2;
@@ -2343,7 +2343,7 @@ namespace TechDrawGui {
         for (auto selected : selection) {
             auto object = selected.getObject();
             if (object->isDerivedFrom(TechDraw::DrawViewDimension::getClassTypeId())) {
-                auto dim = dynamic_cast<TechDraw::DrawViewDimension*>(selected.getObject());
+                auto dim = static_cast<TechDraw::DrawViewDimension*>(selected.getObject());
                 std::string dimType = dim->Type.getValueAsString();
                 if (dimType == needDimType)
                     validDimension.push_back(dim);
diff --git a/src/Mod/TechDraw/Gui/CommandExtensionPack.cpp b/src/Mod/TechDraw/Gui/CommandExtensionPack.cpp
index 33a21b82d3..dc1d4ab0e5 100644
--- a/src/Mod/TechDraw/Gui/CommandExtensionPack.cpp
+++ b/src/Mod/TechDraw/Gui/CommandExtensionPack.cpp
@@ -1403,7 +1403,6 @@ void CmdTechDrawExtensionLockUnlockView::activated(int iMsg) {
         return;
     Gui::Command::openCommand(QT_TRANSLATE_NOOP("Command", "Lock/Unlock View"));
     if (objFeat->isDerivedFrom(TechDraw::DrawViewPart::getClassTypeId())) {
-        auto objFeat = dynamic_cast<TechDraw::DrawViewPart*>(selection[0].getObject());
         bool lockPosition = objFeat->LockPosition.getValue();
         lockPosition = !lockPosition;
         objFeat->LockPosition.setValue(lockPosition);
@@ -1819,8 +1818,11 @@ void CmdTechDrawExtensionAreaAnnotation::activated(int iMsg)
     QString qUserString = asQuantity.getUserString();
     std::string sUserString = Base::Tools::toStdString(qUserString);
 
-    xCenter = (xCenter/totalPoints)/scale;
-    yCenter = (yCenter/totalPoints)/scale;
+    if (totalPoints != 0 && scale != 0.0) {
+        xCenter = (xCenter/totalPoints)/scale;
+        yCenter = (yCenter/totalPoints)/scale;
+    }
+
     // set the attributes in the data tab's fields
     balloon->SourceView.setValue(objFeat);
     balloon->BubbleShape.setValue("Rectangle");
@@ -1871,17 +1873,20 @@ namespace TechDrawGui {
     std::string _createBalloon(Gui::Command* cmd, TechDraw::DrawViewPart* objFeat)
         // create a new balloon, return it's name as string
     {
+        std::string featName;
         TechDraw::DrawPage* page = objFeat->findParentPage();
         page->balloonParent = objFeat;
         Gui::Document* guiDoc = Gui::Application::Instance->getDocument(page->getDocument());
         ViewProviderPage* pageVP = dynamic_cast<ViewProviderPage*>(guiDoc->getViewProvider(page));
-        QGVPage* viewPage = pageVP->getGraphicsView();
-        std::string featName = viewPage->getDrawPage()->getDocument()->getUniqueObjectName("Balloon");
-        std::string pageName = viewPage->getDrawPage()->getNameInDocument();
-        cmd->doCommand(cmd->Doc, "App.activeDocument().addObject('TechDraw::DrawViewBalloon','%s')",
-                       featName.c_str());
-        cmd->doCommand(cmd->Doc, "App.activeDocument().%s.addView(App.activeDocument().%s)",
-                       pageName.c_str(), featName.c_str());
+        if (pageVP) {
+            QGVPage* viewPage = pageVP->getGraphicsView();
+            featName = viewPage->getDrawPage()->getDocument()->getUniqueObjectName("Balloon");
+            std::string pageName = viewPage->getDrawPage()->getNameInDocument();
+            cmd->doCommand(cmd->Doc, "App.activeDocument().addObject('TechDraw::DrawViewBalloon','%s')",
+                           featName.c_str());
+            cmd->doCommand(cmd->Doc, "App.activeDocument().%s.addView(App.activeDocument().%s)",
+                           pageName.c_str(), featName.c_str());
+        }
         return featName;
     }
 
diff --git a/src/Mod/TechDraw/Gui/TaskCustomizeFormat.cpp b/src/Mod/TechDraw/Gui/TaskCustomizeFormat.cpp
index 0e9b7b71b0..9fbbdef103 100644
--- a/src/Mod/TechDraw/Gui/TaskCustomizeFormat.cpp
+++ b/src/Mod/TechDraw/Gui/TaskCustomizeFormat.cpp
@@ -108,17 +108,15 @@ void TaskCustomizeFormat::changeEvent(QEvent *e)
 void TaskCustomizeFormat::setUiEdit()
 {
     setWindowTitle(tr("Customize Format"));
-    if (selectedObject->isDerivedFrom(TechDraw::DrawViewDimension::getClassTypeId()))
+    if (auto dim = dynamic_cast<TechDraw::DrawViewDimension*>(selectedObject))
     {
-        auto dim = dynamic_cast<TechDraw::DrawViewDimension*>(selectedObject);
         isDimension = true;
         std::string dimText = dim->FormatSpec.getStrValue();
         dimRawValue = dim->getDimValue();
         ui->leFormat->setText(Base::Tools::fromStdString(dimText));
     }
-    else
+    else if (auto balloon = dynamic_cast<TechDraw::DrawViewBalloon*>(selectedObject))
     {
-        auto balloon = dynamic_cast<TechDraw::DrawViewBalloon*>(selectedObject);
         isDimension = false;
         std::string balloonText = balloon->Text.getStrValue();
         ui->leFormat->setText(Base::Tools::fromStdString(balloonText));
@@ -191,9 +189,12 @@ void TaskCustomizeFormat::onSymbolClicked()
 {
     // Slot: a symbol PushButton has been clicked
     QObject* senderObj(this->sender());
-    QPushButton* pressedButton = dynamic_cast<QPushButton*>(senderObj);
-    QString pbText = pressedButton->text();
-    ui->leFormat->insert(pbText);
+    QPushButton* pressedButton = qobject_cast<QPushButton*>(senderObj);
+    if (pressedButton)
+    {
+        QString pbText = pressedButton->text();
+        ui->leFormat->insert(pbText);
+    }
 }
 
 void TaskCustomizeFormat::onFormatChanged()