Display elements in mobile only

Hello, i hope somebody can help me. I’ve tried several times to display elements in mobile only. I did everything as explained in this description: Velo Tutorial: Displaying Elements in Mobile Only | Help Center | Wix.com. But it will not work. I can see the element in the mobile and desktop editor but not in the mobile preview.
Who can help me?
Thanks a lot!

There’s a known issue on our end that Preview always returns “desktop” when checking wixWindow.formFactor. Please check your published site and you should be able to see that your elements are hidden on desktop and visible on mobile.

Ohhh…i didn’t know that. Thank you very much!!