The scroll-bar on the side is not functioning. You can't go up and down to search email, even with the arrow keys. Folders column also...scroll bar dysfunctional. When you are check-ticking on your emails, and scroll down to next page, the ticks disappear.
We are not able to replicate this issue, please follow the steps provided in this help article: https://help.yahoo.com/kb/new-mail-for-desktop/browser-troubleshooting-article-sln2891.html
mohib jivan commented
The navigation bars need to be functional. Where are they? If they are not functional, why are they shown on either side of the page? And folders section is not easy to guide up and down