title: UITableView cell reordering drag action unexpectedly stops
body: <p>I'm trying to figure out how to debug the following scenario to understand why UITableView cells won't re-order.</p>
  
  <ol>
  <li>Touch 'Edit' menu item, to put table view into edit mode.</li>
  <li>Edit mode works for deleting cells.</li>
  <li>Try to re-order cells by touching and dragging the re-order control on a cell.</li>
  <li>Cell outline moves in the drag direction a couple of pixels, but then snaps back into it's original position even through my finger is still dragging across the screen.</li>
  </ol>
  
  <p>In code:</p>
  
  <ul>
  <li>UITableViewDelegate: targetIndexPathForMoveFromRowAtIndexPath never gets called.  This would seem consistent with the UI feedback for the cell snapping back to it's original position before it ever gets on top of another cell.</li>
  <li>UITableViewDataSource: canMoveRowAtIndexPath returns true for all rows.</li>
  <li>UITableViewDataSource: moveRowAtIndexPath always gets called as soon as the cell snaps back to it's original position, and the sourceIndexPath and destinationIndexPath values are the same. - </li>
  </ul>
  
  <p>The same view controller code and storyboard work correctly for reordering cells in another project.</p>
  
  <p>I've searched stackoverflow and Google for a day and can't find any reference to what would cause a cell drag event to get canceled.</p>
  
  <p>Any thoughts on how I could approach debugging this issue would be greatly appreciated!</p>