Discover this warning at verbose log level in chrome.
Any <select> tag will log a warning.
The complete message is:

[Violation] Added non-passive event listener to a scroll-blocking 'mousewheel' event. Consider marking event handler as 'passive' to make the page more responsive. See https://www.chromestatus.com/feature/5745543795965952 

• React select component
• jQuery discussion
• React discussion
• https://stackoverflow.com/questions/39152877/consider-marking-event-handler-as-passive-to-make-the-page-more-responsive
• https://github.com/WICG/EventListenerOptions/blob/gh-pages/explainer.md