  Under Jensen's diamond principle $\diamondsuit$, we construct a simple Efimov
space $K$ whose space of nonatomic probability measures $P_{na}(K)$ is
first-countable and sequentially compact. These two properties of $P_{na}(K)$
imply that the space of probability measures $P(K)$ on $K$ is selectively
sequentially pseudocompact and the Banach space $C(K)$ of continuous functions
on $K$ has the Gelfand-Phillips property. We show also that any sequence of
probability measures on $K$ that converges to an atomic measure converges in
norm, and any sequence of probability measures on $K$ converging to zero in
sup-norm has a subsequence converging to a nonatomic probability measure.
