Overlay2 migration

Overlay in Blueprint v6.0 features some breaking changes compared to previous versions. To help you migrate to the new component, we've provided a new component called Overlay2 in @blueprintjs/core v5.9.0+.

Notable changes compared to Overlay

• The child of <Overlay2> must be a native DOM element or utilize React.forwardRef() to forward any injected ref to the underlying DOM element.
• In addition, if you attach your own ref to the child, you must pass the same React.RefObject<HTMLElement> value to <Overlay2> via the childRef prop (we need this to forward along to <CSSTransition>). In this case, you may only supply a single child element (all other children will be ignored).