The highlighting drag-and-drop sibling/parent/child cursor makes it very convenient and easy to create new connections between existing members of a common pedigree. However it also makes it easier to mistakenly link two individuals, eg. an unintended mating connection between siblings. Such a mistake could generally be resolved by undoing a previous edit, but if the editor saves the pedigree, then there is no simple way to undo such a connection without deleting parent and/or child nodes.
A visual pedigree editor should ideally allow one to mouse over a connection and delete the line itself, in the same way that mousing over a node allows one the option of deleting it by clicking 'x'.