Move Spam and Trash above Folders. Now, Spam and Trash are virtually inaccessible if you keep your Folders expanded
I saw you currently have a hint about keeping all folders expanded and this is really important. However, this is unusable right now. When Folders are expanded, it becomes a nightmare to access the Spam folder and since your filters do not work (no matter what tricks you try to make them work), easily checking the Spam folder is a must. If you expand Folders though, access to the Spam folder (and Trash as well) becomes quite hard, especially when you have a lot of folders like me. Please, move Spam (and Trash) above Folders (ideally in the section with Inbox)!

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Nashspacerocket commented
Let me add some research.
When i go into yahoo mail the taskbar overlays part of the last folder and the three dots and the last email. However if i collapse the folders and re-expand them, it works correctly, both the folders and the email side, no overlay. But if i logout and then go back in i get the same behavior. So each day i have to log in, collapse the folders and re-expand them to stop the windows taskbar overlaying the bottom most line in folders and email list. -
Nashspacerocket commented
if you create enough subfolders that you need to scroll, the 3 dots at the bottom after the last folder that contain settings, spam, trash etc are hidden by the windows task bar so you can't access it.
The only way to do it is collapse the subfolders.