This isn't a helpful fix, but rather a me-too. I was having exactly the same problem last night not long before you posted this message. Click "Edit current sequence", and all the extra "stuff" would clear away, the "Exit Editor" button would appear in the upper right, but nothing else would appear. Took me a few tries to see it (and, this was my first upload, so it was massively confusing trying to edit my first sequence and the tools didn't seem to work. ).
Sorry, that's not really a helpful answer, but, just know you're not the only one.