Comparison of V_p and deconvolved FWHM between the [O I] 630 nm line and the [O I] 557 nm (upper panels) and [S II] 406 nm (bottom panels) lines for the NLVC. Red dots indicate sources where the NLVC has been clearly identified in both lines, while blue dots refer to sources where the LVC in the [O I] 630 nm line has been decomposed into a NLVC and a BLVC, while a single component has been identified in the other lines.