Probable-member selection. Only well-measured stars are shown. No quality selection cuts are applied to saturated stars. Panel (a) shows the m_F606W versus m_F606W − m_F814W CMD. Saturated stars with no proper motion measurements and for which is impossible to estimate the membership probability are shown in green. Panel (b) presents the membership probability as a function of m_F606W magnitude, and the selection drawn by hand. In all panels, we highlight in red field stars and in black likely cluster member. Stars that are saturated in at least one filter are shown in blue.