Differences found in the classification of the dominant ionization when using different diagnostics. Each panel comprises a heat-map showing the fraction of objects (color scale and values within each cell) assigned to each type of ionization by a different diagnostic diagram for a different subsample of galaxies (from the top left to bottom right): LTGs, ETGs, X-ray-selected AGNs (X-AGNs), IR-selected AGNs (I-AGNs), UV-optically selected AGNs (O-AGNs), and radio-selected AGNs (R-AGNs). Each heat-map column corresponds to the different ionizing types considered in this work, namely: (i) ionization associated with recent SFGs; (ii) mixed or unknown ionization (Mix/Unk); (iii) ionization usually found in non-star-forming and retired galaxies (RGs), due to hot evolved stars (Binette et al. 1994; Flores-Fajardo et al. 2011), and/or low-velocity shocks (Dopita et al. 1996); and (iv) ionization associated with AGNs and or shocks associated with galactic scale winds (e.g., López-Cobá et al. 2020). On the other hand, each row corresponds to a different diagnostic scheme, including the use of: (i) the classical diagram by Baldwin et al. (1981) that uses O III/Hβ and N II/Hα line ratios (BPT-N2); (ii) the three diagrams by Baldwin et al. (1981) that use the O III/Hβ vs. N II/Hα S II/Hα and O I/Ha line ratios (BPT-all); (iii) the BPT-N2 diagram including a cut in the equivalent width of Hα (BPT-N2+WHa), as described in Sánchez (2020); (iv) the WHaN diagram that uses the N II/Hα and the equivalent width of Hα (WHaN); (v) the diagram introduced by Sánchez et al. (2024) that uses N II/Hα and the velocity dispersion of Hα (WHaD); (vi) the new proposed diagram that uses O III/O II and the equivalent width of Hα (WHaO). Finally, we have three different combinations that use the WHaD and WHaO diagrams: (vii) WHaDoO, (viii) WHaDoO, and (ix) WHaD+O, as described in the text.