Fix Detail Highlight when Detail has no Geometry

- Detail circles were no drawn if detail area did not
  produce any geometry (detail anchor point + radius not
  over original part.

src/Mod/TechDraw/App/DrawViewDetail.cpp

@@ -288,7 +288,13 @@ App::DocumentObjectExecReturn *DrawViewDetail::execute(void)
     testBox.SetGap(0.0);
     BRepBndLib::Add(detail, testBox);
     if (testBox.IsVoid()) {
-        Base::Console().Message("DrawViewDetail - detail area contains no geometry\n");
+//        Base::Console().Warning("DrawViewDetail - detail area contains no geometry\n");
+        TechDrawGeometry::GeometryObject* go = getGeometryObject();
+        if (go != nullptr) {
+            go->clear();
+        }
+        requestPaint();
+        dvp->requestPaint();
         return new App::DocumentObjectExecReturn("DVDetail - detail area contains no geometry");
     }
 

src/Mod/TechDraw/Gui/QGIViewPart.cpp

@@ -331,6 +331,8 @@ void QGIViewPart::drawViewPart()
         return;
     }
     if (!viewPart->hasGeometry()) {
+        removePrimitives();                      //clean the slate
+        removeDecorations();
         return;
     }
 
@@ -754,10 +756,6 @@ void QGIViewPart::drawHighlight(TechDraw::DrawViewDetail* viewDetail, bool b)
         return;
     }
 
-    if (!viewDetail->hasGeometry()) {
-        return;
-    }
-
     auto vp = static_cast<ViewProviderViewPart*>(getViewProvider(getViewObject()));
     if ( vp == nullptr ) {
         return;