A Microsoft file hosting and synchronization service.
Have you tried Jason's trick with closing off the app, then reopening in Landscape mode?
Ys, really, it actually works, pathetic as the case may be.
Good luck, I know very well the frustration!!! I spent days trying to solve it, but as the old saying goes; "insanity is doing the same thing over and over again and expecting different results" is what it drives people to with this type of issue.
We've come to expect that when you rotate a device, the software.....................................just should work........................HOWEVER, in this case ???????