If you want to add a custom item to the top menu, you need to add a 'Language Key' to the language settings before it will show in the menu list. This is how it is done:
In the admin section, go to 'Settings'/'Language Settings' and select, 'Add Key'.
In the 'Key Name' box, type in the word you want to add (the new menu item name), preceded by an UNDERSCORE. Let's say the word you want to add is Milk. The entry must be _Milk
In the box 'String Text For English Language' type the word again, without an underscore and click, 'Save'. Now go back to the admin section and select 'Builders'. From the menu, select 'Navigation Menu'.
From the box 'All Items' select 'New Item'.
Drag the 'New Item' control box into the above box 'Active Items' and place it where you want it to be.
Click on the control box heading 'New Item'. The form 'Edit Item' appears.
In the field, 'System Name', type in the new menu item name (without the underscore)
In the 'Language Key' box, type the word again, but with the underscore (example: _Milk)
In the 'Default Name' box, type in the word again (without the underscore)
Enter your URL
Select your 'Target Window' preference, whether the link will open in a new window (target _blank), or the same window as the page the menu is on.
Finally, don't forget to select 'visible', otherwise it will not show on the menu.
Click 'Save Changes'
Change to 'Tools'/Cache and click 'All'. You should now be able to see the new item in the menu list (after refresh the page).
I hope this will help someone, somewhere.
