message: z-index style not necessary with Portal
diff: @@ -29,7 +29,6 @@ const StyledOverlay = styled.div<StyledOverlayProps>`
  background-color: ${get('overlay.bg')};
  box-shadow: ${get('overlay.popover.boxShadow')};
  position: absolute;
  - z-index: 100;
  min-width: 192px;
  max-width: 480px;
  height: ${props => heightMap[props.height || 'auto']};
  