Looking at Draggable's ''cursorAt'' and Dialog's ''position'' options I note that they use different ways to pass a set of coordinates to the function. Dialog uses an array of offsets from top left, where Draggable uses a hash of either {top: n, left: m} or {bottom: n, right: m} (etc.).

There should probably be a common way to pass coordinates to plugins; possibly by making Draggable's way the default with Dialog's way as a convenience shortcut. Dialog's method can also be extended to allow negative offsets to be relative to the bottom and right edges.