  We explain why the naive definition of a natural exact category structure on
complete, separated topological vector spaces with linear topology fails. In
particular, contrary to arXiv:0711.2527, the category of such topological
vector spaces is not quasi-abelian. We present a corrected definition of exact
category structure which works OK. Then we explain that the corrected
definition still has a shortcoming in that a natural tensor product functor is
not exact in it, and discuss ways to refine the exact category structure so as
to make the tensor product functors exact.
