.sortable( 'cancel' ) cancels whole item drag

.sortable( 'cancel' ) is supposed to behave like this:

Signature:

.sortable( 'cancel' )

Cancels a change in the current sortable and reverts it back to how it was before the current sort started. Useful in the stop and receive callback functions.

If the sortable item is not being moved from one connected sortable to another:

$(this).sortable('cancel');

will cancel the change.

If the sortable item is being moved from one connected sortable to another:

$(ui.sender).sortable('cancel');

will cancel the change. Useful in the 'receive' callback.

The first line works as expected, but the second doesn't. If two sortables A and B are connected and one wants to keep B's content constant, he could use cancel on B so that a drag between A and B would only affect A. But this doesn't work. If for example A's receive event handler has $(ui.sender).sortable('cancel'); and an item is dragged from B to A, both A and B are unchanged. The item is not added to A.