The first toggle in the Menu tab is a setting called Enable Settings In Menu Module. This does exactly what it says, it activates settings created by the Divi Responsive Helper plugin inside the existing Menu module.
You will notice that the Menu module and Theme Options have identical settings. This is because the settings in Theme Options affect the default header menu, while the settings in the Menu module affect just that module. Having the separate settings in the Menu module, a huge breakthrough and introduces many convenient options that can be enabled or disabled per module.
Show/Hide Menu Items
Enable this feature to add new checkmarks in the WordPress navigation menu items to show or hide the menu items on Desktop, Tablet, or Phone. Once enabled, each menu item in Appearance>Menus will have checkmark boxes which allow you to choose on which device sizes you want that particular menu item to be visible.
Choose Navigation Menu Per Device In Menu Module
The Divi Menu module is limited because it only allows you to select one WordPress navigation menu, and that menu shows on all devices. So we hacked the Divi Menu module and added responsive settings to the menu selection dropdown! Now you can choose a completely different navigation menu to show on Desktop, Tablet, and Phone!
Show A Hamburger Menu On Desktop
Opened/Closed Icon Picker For Menu Module
Choose which icons you want to use for both the opened and closed hamburger menu icons. The icon picker allows you to choose any icon included with Divi.
Add Text Beside Hamburger Menu Icon
Enable this feature to show a word or text to the left side the of the hamburger menu icon. This gives the visitor a visual indication or prompt to make it clear that it is the menu.
Show An Open Menu On Mobile
Collapse Mobile Menu Submenus
This feature allows you to collapse the submenus rather than keep them open, which is the default behavior. This really helps tidy up the menu and makes it much shorter as well.
Collapse Submenu When Another One Is Opened
This setting makes any open submenu closes as soon as another submenu is clicked open. This way, there is only one submenu open at one time.
Open/Close Submenus By Clicking Parent Menu Item
This next new setting takes it a step further. After the submenus are collapsed, you can also choose to open and close the submenu by clicking the parent menu item. So for this, just keep in mind that it effectively disables the parent menu link. The parent link becomes the clicking point to open or close the submenu, just like the icon.
Enter the screen width pixel value for the responsive breakpoint for when the menu changes between desktop and mobile versions. This is helpful especially when you have a larger number of menu items that start to overlap due to space issues. Increasing the breakpoint higher than the default 981px allows the hamburger menu to appear on larger device sizes to prevent the ugly and unprofessional stacking issue.