Using MovieMaker 2012 build 16.4.3508.0205 & Windows 8. 

I am using the right-click "split" function to chop up a clip so I can rearrange the parts back into a desired sequence.  Frequently executing a "split" causes all of the clips to disappear, leaving a blank storyboard.  "Undo" brings it all back, but from that point on any "split" causes everything to dissapear.  This seems to happen most frequently when the storyboard contains several clips (from previous "splits" of the original).  It never happens on the first "split".  Everything else seems to work fine for me, but this splitting problem is frustrating as the only recovery seems to be to start completely over.