We are using the new Dropbox embedder to show files on our website. It is working overall, with the exception of excel sheet tabs. The excel sheet loads correctly, but on mobile devices the user cannot switch excel worksheets/tabs. There is an overlay menu that has buttons to switch to full screen or to print. I believe that the overlay is preventing tabs to be switched. If you switch to full screen mode, it is possible to switch worksheets.
You only need to use one or the other, but it looks like you're currently trying to use both. That is, you have both the "dropbox-embed" class on an anchor, as well as using 'Dropbox.embed' to set the embed on that same element. To avoid complications, please just use one of the two methods.