diff --git a/src/Mod/Part/App/GeometryMigrationExtension.cpp b/src/Mod/Part/App/GeometryMigrationExtension.cpp
index 61cda8d6df..2ecebe6298 100644
--- a/src/Mod/Part/App/GeometryMigrationExtension.cpp
+++ b/src/Mod/Part/App/GeometryMigrationExtension.cpp
@@ -35,11 +35,10 @@ TYPESYSTEM_SOURCE_ABSTRACT(Part::GeometryMigrationPersistenceExtension, Part::Ge
 TYPESYSTEM_SOURCE(Part::GeometryMigrationExtension,Part::GeometryExtension)
 
 
-void GeometryMigrationExtension::copyAttributes(Part::GeometryExtension * cpy) const
-{
+void GeometryMigrationExtension::copyAttributes(Part::GeometryExtension *cpy) const {
     Part::GeometryExtension::copyAttributes(cpy);
     static_cast<GeometryMigrationExtension *>(cpy)->ConstructionState = this->ConstructionState;
-    static_cast<GeometryMigrationExtension *>(cpy)->GeometryMigrationFlags  = this->GeometryMigrationFlags;
+    static_cast<GeometryMigrationExtension *>(cpy)->GeometryMigrationFlags = this->GeometryMigrationFlags;
 
     static_cast<GeometryMigrationExtension *>(cpy)->Id = this->Id;
     static_cast<GeometryMigrationExtension *>(cpy)->Flags = this->Flags;
diff --git a/src/Mod/Part/App/GeometryMigrationExtension.h b/src/Mod/Part/App/GeometryMigrationExtension.h
index edfaddd8cb..59375ee4f3 100644
--- a/src/Mod/Part/App/GeometryMigrationExtension.h
+++ b/src/Mod/Part/App/GeometryMigrationExtension.h
@@ -62,16 +62,26 @@ public:
     PyObject *getPyObject() override;
 
 
-    virtual bool getConstruction() const {return ConstructionState;}
-    virtual void setConstruction(bool construction)
-        {ConstructionState = construction; setMigrationType(Construction);}
+    virtual bool getConstruction() const { return ConstructionState; }
 
-    long getId() const {return Id;}
-    void setId(long id) {Id = id; setMigrationType(GeometryId);}
+    virtual void setConstruction(bool construction) {
+        ConstructionState = construction;
+        setMigrationType(Construction);
+    }
+
+    long getId() const { return Id; }
+
+    void setId(long id) {
+        Id = id;
+        setMigrationType(GeometryId);
+    }
+
+    const std::string &getRef() const { return Ref; }
+
+    int getRefIndex() const { return RefIndex; }
+
+    unsigned long getFlags() const { return Flags; }
 
-    const std::string &getRef() const {return Ref;}
-    int getRefIndex() const {return RefIndex;}
-    unsigned long getFlags() const {return Flags;}
     void setReference(const char *ref, int index, unsigned long flags) {
         Ref = ref ? ref : "";
         RefIndex = index;
@@ -103,9 +113,9 @@ class PartExport GeometryMigrationPersistenceExtension : public Part::GeometryPe
 {
     TYPESYSTEM_HEADER();
 public:
-    // Called to save data as attributes in 'Geometry' XML tag
+    // Called to extend 'Geometry' XML tag with additional attributes (eg Id)
     virtual void preSave(Base::Writer &/*writer*/) const {}
-    // Called to save data after 'GeometryExtensions' XML elements
+    // Called to add additional tag after 'GeometryExtensions' XML elements (eg Construction flag)
     virtual void postSave(Base::Writer &/*writer*/) const {}
 };
 
diff --git a/src/Mod/Sketcher/App/ExternalGeometryFacade.cpp b/src/Mod/Sketcher/App/ExternalGeometryFacade.cpp
index ec7dbb7cc8..6a4d249ba2 100644
--- a/src/Mod/Sketcher/App/ExternalGeometryFacade.cpp
+++ b/src/Mod/Sketcher/App/ExternalGeometryFacade.cpp
@@ -170,7 +170,7 @@ void ExternalGeometryFacade::copyFlags(const Part::Geometry* src, Part::Geometry
 
 void ExternalGeometryFacade::setRef(const std::string& ref)
 {
-    if (ref.size() && getId() < 0) {
+    if (ref.empty() && getId() < 0) {
         FC_ERR("Cannot set reference on root geometries");
     }
     else {
@@ -178,14 +178,6 @@ void ExternalGeometryFacade::setRef(const std::string& ref)
     }
 }
 
-// void ExternalGeometryFacade::setRef(const std::string &ref)
-//{
-//     if (ref.size() && getId() < 0)
-//         FC_ERR("Cannot set reference on root geometries");
-//     else
-//         getExternalGeoExt()->setRef(ref);
-// }
-
 PyObject* ExternalGeometryFacade::getPyObject()
 {
     return new ExternalGeometryFacadePy(new ExternalGeometryFacade(this->Geo));
diff --git a/src/Mod/Sketcher/App/ExternalGeometryFacade.h b/src/Mod/Sketcher/App/ExternalGeometryFacade.h
index c1c9cce6df..ac2c2b7dfd 100644
--- a/src/Mod/Sketcher/App/ExternalGeometryFacade.h
+++ b/src/Mod/Sketcher/App/ExternalGeometryFacade.h
@@ -78,6 +78,7 @@ public:
     {
         return getExternalGeoExt()->testFlag(flag);
     }
+
     void setFlag(int flag, bool v = true) override
     {
         getExternalGeoExt()->setFlag(flag, v);
@@ -87,6 +88,7 @@ public:
     {
         return getExternalGeoExt()->getFlags();
     }
+
     void setFlags(unsigned long flags) override
     {
         getExternalGeoExt()->setFlags(flags);
@@ -96,6 +98,7 @@ public:
     {
         return getExternalGeoExt()->isClear();
     }
+
     size_t flagSize() const override
     {
         return getExternalGeoExt()->flagSize();
@@ -105,6 +108,7 @@ public:
     {
         return getExternalGeoExt()->getRef();
     }
+
     void setRef(const std::string& ref) override;
 
     int getRefIndex() const override