Description from Webflow:
Sometimes that overflow parent can be problematic, if it's setup, then you can't really use sticky position.
This is the solution...
1. Element starts off as an absolute placed on the page wherever you like.
2. Once the viewport reaches the top of the element, a class is added to the element. That class is called "sticky".
3. If we click on the menu within webflow. You will see there is a modifier class available called "sticky".
4. If you add that class, you will see what the menu looks like once the class is added, one of the css changes is from position absolute, to position: fixed.
5. Using the sticky modifier you are able adjust what the menu looks like. Once happy with your changes, just remove the modify class so that when scrolling the script can add the class on automatically.