Draggable: Check all parents for fixed positioning when scrolling

Fixes #9612

Author: mikesherov

tests/unit/draggable/draggable_core.js

@@ -182,25 +182,33 @@ test( "#9315: jumps down with offset of scrollbar", function() {
 		});
 });
 
-test( "#5009: scroll not working with parent's position fixed", function() {
+test( "scroll offset with fixed ancestors", function() {
 	expect( 2 );
 
 	var startValue = 300,
-		element = $( "#draggable1" ).wrap( "<div id='wrapper' />" ).draggable({
-			drag: function() {
-				startValue += 100;
-				$( document ).scrollTop( startValue ).scrollLeft( startValue );
-			},
-			stop: function( event, ui ) {
-				equal( ui.position.left, 10, "left position is correct when parent position is fixed" );
-				equal( ui.position.top, 10, "top position is correct when parent position is fixed" );
-				$( document ).scrollTop( 0 ).scrollLeft( 0 );
-			}
-		});
+		element = $( "#draggable1" )
+			// http://bugs.jqueryui.com/ticket/5009
+			// scroll not working with parent's position fixed
+			.wrap( "<div id='wrapper' />" )
+			// http://bugs.jqueryui.com/ticket/9612
+			// abspos elements inside of fixed elements moving away from the mouse when scrolling
+			.wrap( "<div id='wrapper2' />" )
+			.draggable({
+				drag: function() {
+					startValue += 100;
+					$( document ).scrollTop( startValue ).scrollLeft( startValue );
+				},
+				stop: function( event, ui ) {
+					equal( ui.position.left, 10, "left position is correct when parent position is fixed" );
+					equal( ui.position.top, 10, "top position is correct when parent position is fixed" );
+					$( document ).scrollTop( 0 ).scrollLeft( 0 );
+				}
+			});
 
 	TestHelpers.forceScrollableWindow();
 
 	$( "#wrapper" ).css( "position", "fixed" );
+	$( "#wrapper2" ).css( "position", "absolute" );
 
 	element.simulate( "drag", {
 		dx: 10,

ui/draggable.js

@@ -174,7 +174,9 @@ $.widget("ui.draggable", $.ui.mouse, {
 		this.cssPosition = this.helper.css( "position" );
 		this.scrollParent = this.helper.scrollParent( true );
 		this.offsetParent = this.helper.offsetParent();
-		this.offsetParentCssPosition = this.offsetParent.css( "position" );
+		this.hasFixedAncestor = this.helper.parents().filter(function() {
+				return $( this ).css( "position" ) === "fixed";
+			}).length > 0;
 
 		//The element's absolute position on the page minus margins
 		this.positionAbs = this.element.offset();
@@ -236,7 +238,7 @@ $.widget("ui.draggable", $.ui.mouse, {
 
 	_mouseDrag: function(event, noPropagation) {
 		// reset any necessary cached properties (see #5009)
-		if ( this.offsetParentCssPosition === "fixed" ) {
+		if ( this.hasFixedAncestor ) {
 			this.offset.parent = this._getParentOffset();
 		}