Blueprint throwing errors about incompatibilities with React Strict Mode

[bkmartinjr]

Lots of blueprintjs errors from the use of popover2. Unfortunately, will not be fixed until mid-2022 with Blueprint 5.

Ref: https://github.com/palantir/blueprint/wiki/Blueprint-5.0
and palantir/blueprint#3979

Example:

Warning: Legacy context API has been detected within a strict-mode tree.

The old API will be supported in all 16.x releases, but applications using it should migrate to the new version.

Please update the following components: Blueprint4.Portal

Learn more about this warning here: https://reactjs.org/link/legacy-context

Warning: findDOMNode is deprecated in StrictMode. findDOMNode was passed an instance of Transition which is inside StrictMode. Instead, add a ref directly to the element you want to reference. Learn more about using refs safely here: https://reactjs.org/link/strict-mode-find-node

etc.