Allow DrawPage updates to be suspended

src/Mod/TechDraw/App/DrawViewDraft.cpp

@@ -88,6 +88,10 @@ void DrawViewDraft::onChanged(const App::Property* prop)
 
 App::DocumentObjectExecReturn *DrawViewDraft::execute(void)
 {
+    if (!keepUpdated()) {
+        return App::DocumentObject::StdReturn;
+    }
+
     App::DocumentObject* sourceObj = Source.getValue();
     if (sourceObj) {
         std::string svgFrag;