Another idea: we could use the history lines to communicate in a flexible way what we want the browser to auto-open. E.g. auto_open = 2FOFCWT PH2FOFCWT auto_open = 2FOFCWT_fill PH2FOFCWT_fill would ask the viewer to open these two maps when the mtz file is read. Then we could even provide a mechanism for users to select themselves what maps are automatically opened, e.g.: phenix.refine.electron_density_maps { map { mtz_label_amplitudes = my_map.f mtz_label_phases = my_map.phi likelihood_weighted = True obs_factor = 3 calc_factor = 2 kicked = True fill_missing_f_obs_with_weighted_f_model = True viewer_auto_open = True } } This could be taken further: auto_open = important_refine_003.pdb auto_open = 2FOFCWT PH2FOFCWT auto_open = 2FOFCWT_fill PH2FOFCWT_fill Maybe with extra settings: auto_open = 2FOFCWT PH2FOFCWT contour_level=3 rgb=0,0,1 auto_open = 2FOFCWT_fill PH2FOFCWT_fill contour_level=3 rgb=0,1,0 Ralf