  The dipole formalism provides a powerful framework from which parton showers
can be constructed. In a recent paper, we proposed a dipole shower with
improved colour accuracy and in this paper we show how it can be further
improved. After an explicit check at $\mathcal{O}(\alpha_{\mathrm{s}}^{2})$ we
confirm that our original shower performs as it was designed to, i.e.
inheriting its handling of angular-ordered radiation from a coherent branching
algorithm. We also show how other dipole shower algorithms fail to achieve
this. Nevertheless, there is an $\mathcal{O}(\alpha_{\mathrm{s}}^{2})$ topology
where it differs at sub-leading $N_{\mathrm{c}}$ from a coherent branching
algorithm. This erroneous topology can contribute a leading logarithm to some
observables and corresponds to emissions that are ordered in $k_t$ but not
angle. We propose a simple, computationally efficient way to correct this and
assign colour factors in accordance with the coherence properties of QCD to all
orders in $\alpha_{\mathrm{s}}$.
