+ 'post_options' => [ 'value' => 'option' ], #after normal options
+ 'empty_label' => '', #better specify it though, the default might change
+ 'multiple' => 0, # bool
+ 'all_selected' => 0, # useful with multiple
+ 'disable_empty' => 0, # bool (implied by multiple)
+ 'label_showkey' => 0, # bool
+ 'label_callback' => sub { my $record = shift; return "label"; },
+
+ #more params controlling HTML stuff about the <SELECT>