Vertical buttons are available in the not yet released version 2.2.I can only see two arrows on the home menu, for navigating left and right.
I'll check, if an implementation is possible, but it will be probably not with version 2.2.The four arrows in the WMC EPG appear when you hover the mouse near the edges of the visible part of the EPG.
It works well here. I've never seen the screen that you showed when playing a movie. Is it probably from a DVD or Bluray? Most people use mkv's, Avi, mpg, so that's one thing I can imagine. I never played a DVD with MP2 and probably never reached this screen then during skinning. Until your reply and more checking: Right mouse click opens the menu, another right mouse click closes it again.However when watching a movie, no matter how much you move the mouse
Btw: You can find all WMC related changes (also planned or next version) here.