Let $X$ be a Feller process that has strong Feller property.
In this paper, we investigate the Feller as well as strong
Feller properties of the semigroups generated by multiplicative
functionals of $X$ in open sets. Special attention is given
to the Feynman-Kac and Girsanov transforms of $X$. Three examples
of local Kato class measure that are not of Kato class are
given in the last section so that Feller and strong Feller
properties hold for corresponding Feynman-Kac semigroup of
$X$ in open sets.