In case you’re editing a page and you see some elements being dimmed (transparent) and red border, it means this element is hidden on a breakpoint.
For example in Milano demo, when editing with Elementor, you should see this section:
This means that this section is hidden for desktops and likely visible on mobiles or tablets.
This is a simple technique where you kind of duplicate the content, customize each one for its particular breakpoint, and hide them where they’re not looking ok.