jsPlumb function that I'm having issues with

gistfile1.js

  	var adjustForParentOffsetAndScroll = function(xy, el) {

			var offsetParent = null, result = xy;
			if (el.tagName.toLowerCase() === "svg" && el.parentNode) {
				offsetParent = el.parentNode;
			}
			else if (el.offsetParent) {
				offsetParent = el.offsetParent;					
			}
			if (offsetParent != null) {
				var po = offsetParent.tagName.toLowerCase() === "body" ? {left:0,top:0} : _getOffset(offsetParent, _currentInstance),
					so = offsetParent.tagName.toLowerCase() === "body" ? {left:0,top:0} : {left:offsetParent.scrollLeft, top:offsetParent.scrollTop};					

				// i thought it might be cool to do this:
				//	lastReturnValue[0] = lastReturnValue[0] - offsetParent.offsetLeft + offsetParent.scrollLeft;
				//	lastReturnValue[1] = lastReturnValue[1] - offsetParent.offsetTop + offsetParent.scrollTop;					
				// but i think it ignores margins.  my reasoning was that it's quicker to not hand off to some underlying					
				// library.
				
        //FIXME - this line *seems* to fix the issue of this thing going bonkers with the end point creation,
        // but I can't be sure that it will work, since I haven't tracked down what the actual problem is.
        //result[0] = xy[0] - 60;
				result[0] = xy[0] - po.left + so.top;
				result[1] = xy[1] - po.top + so.top;
			}
		
			return result;
			
		};