Index: ui.draggable.js
===================================================================
--- ui.draggable.js	(revision 4369)
+++ ui.draggable.js	(working copy)
@@ -94,6 +94,7 @@
 			var elementPosition = { left: this.elementOffset.left - this.offsetParentOffset.left, top: this.elementOffset.top - this.offsetParentOffset.top };
 			this._pageX = e.pageX; this._pageY = e.pageY;
 			this.clickOffset = { left: e.pageX - this.elementOffset.left, top: e.pageY - this.elementOffset.top };
+			this.helperFixed = this.helper.css('position') == 'fixed';
 			var r = this.helper.css('position') == 'relative';
 
 			//Generate the original position
@@ -148,7 +149,10 @@
 		drag: function(e) {
 
 			//Compute the helpers position
-			this.position = { top: e.pageY - this.offset.top, left: e.pageX - this.offset.left };
+			this.position = {
+				top: e.pageY - this.offset.top - ( this.helperFixed ? Math.max(document.documentElement.scrollTop, document.body.scrollTop) : 0 ),
+				left: e.pageX - this.offset.left - ( this.helperFixed ? Math.max(document.documentElement.scrollLeft, document.body.scrollLeft) : 0 )
+			};
 			this.positionAbs = { left: e.pageX - this.clickOffset.left, top: e.pageY - this.clickOffset.top };
 
 			//Call plugins and callbacks