[TD]refactor scene/view/mdi

- move scene related functions out of mdiViewPage
  and QGVPage.
- route requests for scene/view/mdi through
  ViewProviderPage

src/Mod/TechDraw/App/DrawRichAnno.cpp

@@ -79,8 +79,11 @@ void DrawRichAnno::onChanged(const App::Property* prop)
 //NOTE: DocumentObject::mustExecute returns 1/0 and not true/false
 short DrawRichAnno::mustExecute() const
 {
-    if (!isRestoring() && AnnoText.isTouched()) {
-        return 1;
+    if (!isRestoring()) {
+        if (AnnoText.isTouched() ||
+            AnnoParent.isTouched()) {
+            return 1;
+        }
     }
 
     return DrawView::mustExecute();
@@ -101,6 +104,22 @@ DrawView* DrawRichAnno::getBaseView() const
     return dynamic_cast<DrawView*>(AnnoParent.getValue());
 }
 
+//finds the first DrawPage in this Document that claims to own this DrawRichAnno
+//note that it is possible to manipulate the Views property of DrawPage so that
+//more than 1 DrawPage claims a DrawRichAnno.
+DrawPage* DrawRichAnno::findParentPage() const
+{
+//    Base::Console().Message("DRA::findParentPage()\n");
+    DrawPage *page = nullptr;
+    if (AnnoParent.getValue() != nullptr) {
+        DrawView* parent = dynamic_cast<DrawView*>(AnnoParent.getValue());
+        page = parent->findParentPage();
+    } else {
+        page = DrawView::findParentPage();
+    }
+
+    return page;
+}
 
 PyObject *DrawRichAnno::getPyObject()
 {