This option is intended for advanced (expert) use. It is particularly useful when resolving conflicts with other platforms, advertising systems, your own sticky website elements, or specific page layouts where precise layer control is necessary.
Recommendation:
Only set a custom z-index if the campaign conflicts with other elements of the page and Mailocator's automatic behavior is not suitable. An incorrectly selected value may result in the campaign being overlaid or, conversely, unintentionally covering important website content.
An inappropriate z-index can cause the campaign to become partially or completely invisible because it will be overlaid by other elements on the page. Therefore, only use this setting if you know exactly which layers are on the page.