Today I could not get the email platform to react to clicks at all. I keep getting "the long running script message". Yesterday it was reacting like this: When clicking on the select boxes it takes 2 seconds to see the checkmark. Also when typing in the app the lag period for key strokes can be up to 10 seconds. So I agree with the others comments, you should return to classic mail. I am switching to Chrome and Edge for reading and answering emails.
BTW I can't sign in to Yahoo yet to submit this post. Another bug that happens frequently.
How can I forward this message to technical support and the Yahoo email decision makers?