VPM, as 2D histogram diagram, of the stars in the cluster regions within the given radius r from its centre. Yellow areas are representative of over-densities, which become green and blue when the density decreases. White dot circles depict the 1σ, 2σ, and 3σ from the mean cluster PM value. On the top and on the right panels, we show the corresponding PM histograms, pmra (blue), and pmdec (red), respectively. We use a different bin size depending on the crowding of the areas. We add an insert for the VVV-CL160 cluster in order to make the PM over-density much more visible.