Ohba's chromatic-choosability conjecture

For a graph $G$, let $\chi(G)$ be its chromatic number, and let $\chi_\ell(G)$ be its list chromatic number. A graph is chromatic-choosable when $\chi_\ell(G)=\chi(G)$. Ohba's conjecture. Any graph $G$ with at most $2\chi(G)+1$ vertices is chromatic-choosable. The supplied text says this conjecture was proved by Noel et al.; the bound is tight, since examples with $2\chi(G)+2$ vertices are not chromatic-choosable.