User blog comment:Rupert Giles/Layout Changes: Breakpoints and Typography/@comment-5238398-20150601025624/@comment-452-20150602151858

I agree. Perhaps instead of 2 giant preview buttons, having all 4 preview options as smaller icons. (Like the size of the icons with the right rail collapsed.)

Since it has been said that the preview buttons aren't working anyway, what's to lose by making them a little smaller?

Of course, having the 4 icons present with the right rail collapsed might be a bit much, but since having the right rail collapsed seems to be considered an edge case which is barely supported anyway, it might be best to simply go back to a single "preview" button in that mode and only show the individual preview buttons with the right rail expanded.