Anchor Point Square

This has been bugging me for a while - and I am sure there is a quick fix.

When dragging anchor points with the direct selection tool this white square often appears, right where I want to click and drag the anchor handle. If I do click on it, I lose the whole selection, and have to select the path again and try to hit that anchor dragger again. I've attached a screen grab - but my mouse (and handles) disappeared when I captured it - but that pesky white square is still there.

How do I get rid of this damn thing?