Disabling proxy does not disable proxy

[Jigoku]

*** unhandled exception in callback:
***   '' is not a valid URI scheme at ./alluvion-gtk.pl line 611.
***  ignoring at ./alluvion-gtk.pl line 596, <FILE> line 7.

proxy is enabled by issuing:

$ua->proxy([ 'http', 'https' ], "http://".$settings{"proxy_addr"}.":".$settings{"proxy_port"});

when disabling....

$ua->proxy(undef, undef);

THIS is invalid