If you're facing an issue with a dropdown in a Webflow collection list opening under the CMS item below it, even after adjusting the z-index and position, there are a few things you can try to resolve the issue:
1. Check the parent container: Make sure that the parent container of the dropdown has its position property set to relative or absolute. If the parent container doesn't have a position set, the z-index value might not work as expected.
2. Review the z-index values: Double-check the z-index values of the elements involved, including the dropdown, the CMS item, and any potential overlapping elements. Ensure that the dropdown has a higher z-index value than the CMS item below it.
3. Adjust the stacking context: Sometimes, the stacking context of an element can affect how z-index works. If you have any parent elements with their own z-index values, it could interfere with the stacking order of the dropdown. In such cases, you can try adjusting the z-index values of those parent elements or consider moving the dropdown element to another parent element.
4. Utilize z-index on containers: Instead of applying the z-index directly to the dropdown itself, try applying it to the parent containers of both the dropdown and the CMS item. This can help create a separate stacking context for the dropdown and prevent any interference from other elements.
5. Review any custom code or interactions: If you have custom code or interactions applied to the dropdown or any related elements, it's worth checking them for any conflicting styles or instructions that might affect the dropdown's positioning.
6. Test in different browsers: Sometimes, browser-specific rendering issues can cause unexpected behavior with z-index and positioning. Test your site in multiple browsers to see if the issue persists across all of them or if it's limited to a particular browser.
If after going through these steps you're still experiencing the issue, I recommend reaching out to Webflow support or the Webflow community forums for further assistance. Providing them with your project's read-only link can help them understand the issue better and provide more specific guidance.