Removed obsolete member variable GLCanvas3D::m_color_by

src/slic3r/GUI/GCodeViewer.cpp

@@ -2306,7 +2306,7 @@ void GCodeViewer::load_shells(const Print& print, bool initialized)
         }
 
         size_t current_volumes_count = m_shells.volumes.volumes.size();
-        m_shells.volumes.load_object(model_obj, object_id, instance_ids, "object", initialized);
+        m_shells.volumes.load_object(model_obj, object_id, instance_ids, initialized);
 
         // adjust shells' z if raft is present
         const SlicingParameters& slicing_parameters = obj->slicing_parameters();