Update on "inactive product sort listbox" bug: The bug doesn't show in IE10, but it does in Firefox 21.0 (Windows 7 x64).
It does seem to be a bug specific to the "resort" theme; as a test I tried clicking on "shop" in the "canvas" demo, and the product sort list box worked OK under Firefox 21.0.
Which is all I'm going to say about that bug. Now how can I simply make the (sometimes) problematic product sort listbox go away entirely? As I mentioned above, I tried inserting
remove_action( 'woocommerce_pagination', 'woocommerce_catalog_ordering', 20 );
into
public_html/wp-content/themes/resort/functions.php
but to no effect...