Phase space distribution of Progenitor 4 by Koppelman et al. (2019b) on two different orbits after 8 Gyr of integration time in a potential with p = 1.02, q = 1.19. Particles within a local volume selection, that is, d < 2.5 kpc, are shown in black. For comparison, the hiL and loL HS stars are shown in red and blue, respectively. The top two rows show the particles of Progenitor 4 at the present day after it has been re-centred and integrated forward from the 6 D phase-space coordinate of a subclump star 8 Gyr ago, which is resonantly trapped on the Ω_ϕ:Ω_z = 1:1 resonance. Consequently, a large part of the Progenitor 4 particles is resonantly trapped, as is evident from the substructure in configuration space, the flattened particle distribution in the (y, z) plane and the low $\frac{N\left(v_z^{+}\right)}{N\left(v_z^{-}\right)}\sim 0.01$ ratio. The bottom two rows show particles of Progenitor 4 at the present day after it has been re-centred and integrated forward from the 6 D phase-space coordinate of a loL star 8 Gyr ago, which is on a z-tube orbit. The particles appear more mixed, as they show less substructure in configuration space, have a more diffuse velocity distribution and a higher $\frac{N\left(v_z^{+}\right)}{N\left(v_z^{-}\right)}\sim 0.7$ ratio.