This also happened to a friend of mine (Who's got the exact same S6 Edge+ as I, with the same Marshmallow and standard e-mail app versions). However, I can still use "swipe to the left to delete messages". Also his mail screen shows a full bottom line with create new mail, whilst mine shows a circle with plus sign to do the same thing. We do have the same version of the standard email app and the same version of marshmallow. I've tried settings that presumably would make his phone behave like mine, but to no avail. What's happening here?