Left: de-reddened CMD for all the ϖ-background sources in Baade’s Window, cleaned from foreground contaminants using Gaia EDR3 parallaxes. Colour is proportional to the logarithm of the density of sources. Middle: same CMD, colour-coded by the mean value of the proper motion in Galactic longitude. Right: same CMD, colour-coded by the mean value of the proper motion in Galactic latitude. To compare the proper motion values to their typical uncertainty in Gaia EDR3 (see Fig. 2), we note that i₀ = 17 corresponds roughly to G = 18.5.