When checking off Yahoo Mail for delete (10 to 20). Clicking delete, will most of the time do the delete. When a large amount of e mails are checked for delete, 30 or so, clicking delete will fade the selected e mails but nothing more happens. Only solution I have found, exit Firefox, re-enter the Firefox Browser, recheck the same e mail and try delete again. Usually works the second time. I do not have the time to check e mail twice for delete as there are over 1,000 per day. Windows 8.1.

This function works without any problem in Chrome, which I now use to read Yahoo Mail.