Overview of the VPD and CMD of stars with E-G PMs. In the VPD on the left, we selected members of NGC 6397 (black points) as those objects having a PM within 2 mas yr⁻¹ of the bulk motion of the cluster (red circle). All other stars are considered background or foreground field populations and are shown in green. All objects, including those saturated, are shown for completeness. The two groups of stars are then plotted in J_E as a function of (J_E-H_E) on the right. Our PMs are effective in discriminating between the various populations in the field. As a reference, we show in grey all other stars in the catalogue that do not have a PM measurement because they are fainter than the Gaia limit. The main limitation of our investigation is the shallow first-epoch Gaia catalogue used to compute PMs. Only 10% of points are shown for clarity.