I have installed the Post Types Order (PTO) plugin with RT-Theme 10. This enabled me to re-order the products on my site manually like I needed to do – so far so good.
However, that plugin has introduced a problem with disappearing left-hand menu on the product category pages used by RT Theme 10:
– When I click on a product category, the left hand menu disappears.
– The products are still listed, so I can click on a product thumbnail and move on to a product page.
– When the product page opens, the menu appears again and works fine.
Disabling the PTO plugin makes the menu work again.
So: there is evidently some sort of conflict between the category pages of this theme, and the PTO plugin.