Inconsistent port usage in redirects
Currently it is not possible to set up valid redirects with ports. One can enter a "<host>:<port>" as
source_host but this will be dropped again on next form display since the
SourceHost evaluation marks the host as invalid.
However, a port must be set here since the
RedirectHandler does respect this. If redirects are set up without port, there is no match and the redirects won't work.