Top panel: variability in u and r bands for the stars in the three correlation groups. Central panel: variability in u − r vs. stellar effective temperature. Bottom panel: variability in u − r vs. the Spearman correlation coefficient. Top and bottom panels: different symbols are used to mark stars in three different ranges of effective temperature, roughly corresponding to M, K, and G stars. Top and central panels: different colors are used to plot stars in the three correlation groups. Despite the large spread observed, the plots suggest a slightly larger median variability in color for the anti-correlated sources.