Fixed selection after cut command

src/slic3r/GUI/Plater.cpp

@@ -4656,6 +4656,13 @@ void Plater::cut(size_t obj_idx, size_t instance_idx, coordf_t z, bool keep_uppe
 
     remove(obj_idx);
     p->load_model_objects(new_objects);
+
+    Selection& selection = p->get_selection();
+    size_t last_id = p->model.objects.size() - 1;
+    for (size_t i = 0; i < new_objects.size(); ++i)
+    {
+        selection.add_object((unsigned int)(last_id - i), i == 0);
+    }
 }
 
 void Plater::export_gcode()