Looking to access your theme's code or language options with Shopify's new theme editor layout?
In your Shopify admin click on Online store > Themes
Next to the theme that you want to edit click on the Menu button which is a small square with 3 blue dots
This will open a submenu of options which includes: Edit HTMl / CSS and Edit Language
The Mega Dropdown contains 4 sections each of which can carry a link list from the Navigation section of your admin.
This Mega Dropdown needs a parent link assigning to it in order to appear when that link is hovered.
As standard we have assigned this to the Catalog link which is a default in all new Shopify stores.
If you would like to change this to show when a different link is hovered simply add the name of that link Exactly as you have entered it within the main menu link list
If your Main Menu contains a link typed as: Shop Now and this will trigger the mega dropdown simply type Shop Now into the field within the customise theme > Navigation section.
From your Online Store > Navigation > Main Menu Link list
Make note of the name of the link and the Case it is typed in as... For the Example we are choosing: Explore
In Themes > customise theme > Navigation Re-Type the Link title into the Mega Dropdown Link Text box.
Click Save and then test the link on your Store Front.
For further illustration please see this video
Automatic mega menus
As an added extra in the Fashionopolism theme we have also implemented code to help customers who face the problem of long menus within their drop-downs - this is quite a common issue especially when creating lists of brands within your store.
Within the Navigation section of your theme options you will see a drop-down menu titled: Links per multi column dropdown which allows you to choose a value between 4 and 15.
This works if you have a menu that has more links than the number you have selected within that list.
For instance if you have a dropdown with a big list of links you can define the number of links that will be shown in each column up to a total of 4 columns.
So if you have a large store that has in excess of 60 brands then you can break this into 4 columns of 15.
If you have more than number chosen x 4 then the remainder of links will automatically display to the left side without further math required to break up the menus beyond that count.