If you find that your Divi theme's submenu link items disappear when scrolling down, it is possible that this is actually the result of some counter-intuitive behavior of Divi's own settings.
In "Divi > Theme Customizer > Header & Navigation" the "Fixed Navigation Settings > Primary Menu Link Color" option overrides the "Primary Menu Bar > Dropdown Menu Text Color" setting.
If "Primary Menu Bar > Dropdown Menu Background Color" matches the "Fixed Navigation Settings > Primary Menu Link Color", the submenu links will have the same color as the submenu background and won't be visible when scrolling down activates the fixed header.
To fix this, either choose non-conflicting colors for these settings, or you can manually override the submenu link color with:
#top-menu ul.sub-menu a { color:white !important; }
Related Post: Adding CSS to the Divi Theme
Hi, for some reason every time I go into the Theme Customizer, the Fixed Navigation Settings disappears? Even if I click on it, it will not go to the settings.
Hi Amy, I haven't come across this issue before, but if you'd be willing to let me log into the site I'll try my best to work out what's going on. You can send me login details via the contact form. Thanks!
I'm trying to find a solution to this myself. Did you ever find out a solution?
Hey Amy and luther, I think this might be a result of using a header built in the theme builder. See here:
Fix "Header & Navigation" Options Missing from Customizer
You are a life saver! This is the only work around to this problem that I have found. I was pulling my hair out.
I'm glad it helped, Sarah! Thanks!
Thank you!
You're welcome, Tim!