Indeed big problem
I tried and it seems possible to move (or delete) it changing the contentmargins, like Sunbeam said in start menu properties, more precisely : Start > StartMenu > Panels > Aero > Top > PlacesList (i put for example: 3, 15, 0, 5)
and i get this result, the arrow doesn't appear in this case
Normal:
Moved to left :
to delete it, , try "-50" instead of "15"