It is possible to move vertices in the UV view while you are in face mode.
Reproduction path:
1-create a cube,select it.
2-select uv window do not select any faces.
3-put mouse over where vertex is,left click and move.
Thread: http://www.delgine.com/forum/viewtopic.php?p=33680#33680
Fix available here:
https://sourceforge.net/tracker/?func=detail&aid=2969831&group_id=293758&atid=1241129