  A few properties of the nonminimal vector interactions in the
Duffin-Kemmer-Petiau theory are revised. In particular, it is shown that the
space component of the nonminimal vector interaction plays a peremptory role
for confining bosons whereas its time component contributes to the leakage.
Scattering in a square step potential with proper boundary conditions is used
to show that Klein's paradox does not manifest in the case of a nonminimal
vector coupling.
