ObjectList::paste_objects_into_list() refactored to call front end / back end synchronization and scene refresh only once

src/slic3r/GUI/GUI_ObjectList.cpp

@@ -487,12 +487,13 @@ void ObjectList::paste_objects_into_list(const std::vector<size_t>& object_idxs)
     for (const size_t object : object_idxs)
     {
         add_object_to_list(object);
-        m_parts_changed = true;
-        parts_changed(object);
-
         items.Add(m_objects_model->GetItemById(object));
     }
 
+    m_parts_changed = true;
+    wxGetApp().plater()->changed_objects(object_idxs);
+    m_parts_changed = false;
+
     select_items(items);
 #ifndef __WXOSX__ //#ifdef __WXMSW__ // #ys_FIXME
     selection_changed();

src/slic3r/GUI/Plater.cpp

@@ -3714,6 +3714,36 @@ void Plater::changed_object(int obj_idx)
     this->p->schedule_background_process();
 }
 
+void Plater::changed_objects(const std::vector<size_t>& object_idxs)
+{
+    if (object_idxs.empty())
+        return;
+
+    auto list = wxGetApp().obj_list();
+    wxASSERT(list != nullptr);
+    if (list == nullptr)
+        return;
+
+    if (list->is_parts_changed()) {
+        for (int obj_idx : object_idxs)
+        {
+            if (obj_idx < p->model.objects.size())
+                // recenter and re - align to Z = 0
+                p->model.objects[obj_idx]->ensure_on_bed();
+        }
+        if (this->p->printer_technology == ptSLA) {
+            // Update the SLAPrint from the current Model, so that the reload_scene()
+            // pulls the correct data, update the 3D scene.
+            this->p->update_restart_background_process(true, false);
+        }
+        else
+            p->view3D->reload_scene(false);
+    }
+
+    // update print
+    this->p->schedule_background_process();
+}
+
 void Plater::schedule_background_process()
 {
     this->p->schedule_background_process();    

src/slic3r/GUI/Plater.hpp

@@ -162,6 +162,7 @@ public:
     void reslice();
     void reslice_SLA_supports(const ModelObject &object);
     void changed_object(int obj_idx);
+    void changed_objects(const std::vector<size_t>& object_idxs);
     void schedule_background_process();
     void fix_through_netfabb(const int obj_idx, const int vol_idx = -1);
     void send_gcode();