On a test site, with Propulsion theme, if I have woocommerce installed and utilize the sub-nav, the children links show up with grey text and are visible. If I do not have woocommerce installed but set up a submenu, the children links show up with white text and are not visible. I set this up on three different sites. On one site the first child link in each sub-nav item was black with the rest of the links showing up white making them invisible.
I am not sure if it is just me or not.
I am using Safari 5.1.1 and the grey box style setting in propulsion with no other plug-ins installed
This is definitely a possibility. You can modify the display of the sub menu style with the following css put into either your custom.css or Quick CSS (you’ll need to add a color code, here is a quick tool for it http://html-color-codes.info ) :