Glyphs mini: can't disable grid snapping when grid is visible

I am trying to use Glyphs mini to make minor alterations to shapes so they better fit a pixel grid. With a grid value set (say 64), I don’t seem to be able to drag any anchors without them snapping to a grid intersection. Is there a modifier key to disable this snapping in one or both directions? If I disable the grid I then have no guidelines to line up my anchors against.

The grid is intended for everything to snap. Via the context menu, you can create global guidelines and then set the document grid back to 1.