If you set a negative one (-1) for z-index on a section, the buttons and slider indicator inside the section becomes unclickable in the front end.
In the bricks builder interface, all the elements in the section with negative one z-index becomes unclickable as well (the effect is not immediate, only when you reopen the builder will you experience this).
Work around: minimum z-index is zero.
Not sure if this is intentional, but allowing a negative z-index would speed up arranging things since the default for all elements is presumed to be zero.
This behavior aligns with standard CSS functionality. A negative z-index positions elements behind their container, making them unclickable. This is not specific to Bricks but how CSS operates in general.
The unclickable elements are still visible. I did not say they are behind the container. I do this quite often if I want border shadows to display correctly between sections.
Sorry for the confusion. I never thought the -1 z-index was inherited in all elements under the section. I presumed the button remained at default 0; hence, me thinking something is wrong.