diff --git a/src/libslic3r/Model.cpp b/src/libslic3r/Model.cpp
index b734f1108..250c1c968 100644
--- a/src/libslic3r/Model.cpp
+++ b/src/libslic3r/Model.cpp
@@ -699,14 +699,6 @@ void ModelObject::clear_volumes()
     this->invalidate_bounding_box();
 }
 
-void ModelObject::reset_volumes_idxs()
-{
-    for (ModelVolume *v : this->volumes)
-    {
-        v->set_new_unique_id();
-    }
-}
-
 ModelInstance* ModelObject::add_instance()
 {
     ModelInstance* i = new ModelInstance(this);
diff --git a/src/libslic3r/Model.hpp b/src/libslic3r/Model.hpp
index cf6459dd5..b02862203 100644
--- a/src/libslic3r/Model.hpp
+++ b/src/libslic3r/Model.hpp
@@ -200,9 +200,6 @@ public:
     void                    clear_volumes();
     bool                    is_multiparts() const { return volumes.size() > 1; }
 
-    // set a new unique id to all volumes
-    void                    reset_volumes_idxs();
-
     ModelInstance*          add_instance();
     ModelInstance*          add_instance(const ModelInstance &instance);
     ModelInstance*          add_instance(const Vec3d &offset, const Vec3d &scaling_factor, const Vec3d &rotation);
diff --git a/src/slic3r/GUI/GLCanvas3D.cpp b/src/slic3r/GUI/GLCanvas3D.cpp
index 3ab08b773..b918ae7ca 100644
--- a/src/slic3r/GUI/GLCanvas3D.cpp
+++ b/src/slic3r/GUI/GLCanvas3D.cpp
@@ -4087,7 +4087,7 @@ void GLCanvas3D::reload_scene(bool refresh_immediately, bool force_full_scene_re
 						volume->extruder_id = extruder_id;
 
                     // updates volumes transformations
-                    volume->set_instance_transformation(mvs->model_volume->get_object()->instances[volume->instance_idx()]->get_transformation());
+                    volume->set_instance_transformation(mvs->model_volume->get_object()->instances[mvs->composite_id.instance_id]->get_transformation());
                     volume->set_volume_transformation(mvs->model_volume->get_transformation());
                 }
             }
diff --git a/src/slic3r/GUI/GUI_ObjectList.cpp b/src/slic3r/GUI/GUI_ObjectList.cpp
index 5a98c5254..3948cf686 100644
--- a/src/slic3r/GUI/GUI_ObjectList.cpp
+++ b/src/slic3r/GUI/GUI_ObjectList.cpp
@@ -946,7 +946,6 @@ bool ObjectList::del_subobject_from_object(const int obj_idx, const int idx, con
             return false;
         }
         (*m_objects)[obj_idx]->delete_instance(idx);
-        (*m_objects)[obj_idx]->reset_volumes_idxs();
     }
     else
         return false;