In the meantime, adding something like this to whatever custom python extensions file you use seems to do the trick:
def set_new_atom_b_fac_to_mean(): mol_id=active_residue()[0] mean_b=average_temperature_factor(mol_id) set_default_temperature_factor_for_new_atoms(mean_b) add_simple_coot_menu_menuitem(menu, "Set Bfac for new atoms to mean B for active mol",lambda func: set_new_atom_b_fac_to_mean())
