Let E be a separable
Fréchet lattice. It is shown that a solid convex set X with void interior in E is
supported at each of its boundary points if and only if the span of X is not dense in
E. This result then is applied to the case of solid convex sets with void interior in real
Fréchet spaces with an unconditional Schauder basis and in the real Banach lattice
C(S), S compact Hausdorff.