Combined “HRD” for the manually selected candidate members of the four stellar groups identified in Fig. 4. The symbols are coloured according to the so-called BP-RP flux excess from Gaia DR2. For a precise definition and for extensive explanations, see the DR2 documentation. In short: High values of this quantity indicate unresolved double stars with disturbed Gaia DR2 colours. This quantity is shown here in order to indicate that the single dark dot at the top is not due to a real giant belonging to the cluster(s), but to a very probably incorrect colour. Similarly, most of the candidate members far left of the main sequence at the bottom are very probably true members, but with disturbed colours.