Some WordPress plugins or Javascript components that depend on scrolling mechanisms such as sticky menus, animations on scroll, parallax effects etc. might not work if the browser's scroll bar is disabled.

In order to make them work on the fullPage.js plugin for WordPress, make sure to enable the scroll bar on the fullPage.js configuration by setting to active the option "Scrolling > Scroll Bar". 

This option determines whether to use scrollbar for the site or not. In case of using scroll bar, the autoScrolling/snap functionality will still work as expected. The user will also be free to scroll the site by dragging the scroll bar and fullPage will fit the section in the screen when scrolling ends.