I got it working by using position: fixed; on the class element CSS that unhides the tooltip when the target element is hovered. I gave the fixed positioning top and left position values so the to the tooltip box avoids the tabs. They can’t be under them if they’re not near them :).
I corrected the z-index attributes by giving the tooltip z-index;3; the active tab z-index: 2; and every other element z-index:1;.
I also gave the tooltiptext a custom tiptext class when it’s being hovered over so it wasn’t invading the tooltip when it was active.