Disabling drag if Shift key is held down

Question

I have an image that I've set up with jQuery UI to be draggable. This works fine but now I'd like to be able to Shift-drag on the image to draw a box on the image and not have it move. So if the Shift key is held down I don't want to do the drag.

I've tried putting

if(e.shiftKey)return; 

at the top of the drag_start, dragging, and drag_stop functions but this doesn't do anything because the drag operation seems to be done internally in jQuery UI and the calls to drag_start, dragging and drag_stop are just courtesy calls to let you know what jQueryUI is currently doing.

Is there a way to disable the drag if the Shift key is held down?

Thanks

(For more information on this see my "answer" farther below with a jsfiddle.)

Answer 1

How about on start_drag if shift key then return false; (don't initiate drag)

function box_start_drag(e, ui) {
    if(e.shiftKey)
        return false;
}

Fiddle

Or to stop dragging any time shift is held down. Put the return false in the drag method as Dom suggests in the comments below.