message: getBoundingClientRect x and y to left and top
diff: @@ -58,8 +58,8 @@ class TooltipPortal extends React.Component {
  return {
  width: targetBounds.width,
  height: targetBounds.height,
  - x: targetBounds.x - portalBounds.x,
  - y: targetBounds.y - portalBounds.y
  + x: targetBounds.left - portalBounds.left,
  + y: targetBounds.top - portalBounds.top
  };
  }
  