Proper motions of stars enclosed within different CMD regions (see Table 3 for details). Each point corresponds to the median of at least 500 stars. Different colours indicate regions taken from areas dominated by SMC stars (black squares), 47 Tuc stars (magenta triangles), and mixed stars (cyan dots). Centre of mass proper motion measurements from the literature for both the SMC and 47 Tuc are indicated by empty squares whose sizes correspond to their statistical uncertainties. For the SMC the red rectangles (from smallest to largest) give the values from Kallivayalil et al. (2013), Costa et al. (2011), Vieira et al. (2010), respectively, and for 47 Tuc the blue rectangle gives the value from Anderson & King (2003).