diff --git a/demos/tooltip/custom-style.html b/demos/tooltip/custom-style.html
index 4d48616cb..633da3d95 100644
--- a/demos/tooltip/custom-style.html
+++ b/demos/tooltip/custom-style.html
@@ -13,76 +13,67 @@
 	<script>
 	$(function() {
 		$( ".demo" ).tooltip({
-			open: function(event, ui) {
-				$("<div>").addClass("arrow").appendTo(ui.tooltip);
-			},
 			position: {
-				my: "center bottom",
+				my: "center bottom-20",
 				at: "center top",
-				offset: "0 -20px"
+				using: function( position, feedback ) {
+					$( this ).css( position );
+					$( "<div>" )
+						.addClass( "arrow" )
+						.addClass( feedback.vertical )
+						.addClass( feedback.horizontal )
+						.appendTo( this );
+				}
 			}
 		});
 	});
 	</script>
 	<style>
-	label {
-		display: inline-block;
-		width: 5em;
-	}
-	.demo {
-		margin: 10em 0 0 10em;
-	}
 	.ui-tooltip, .arrow:after {
-	  background: black;
-	  border: 2px solid white;
+		background: black;
+		border: 2px solid white;
 	}
 	.ui-tooltip {
-	  display: inline-block;
-	  position: relative;
-	  padding: 10px 20px;
-	  color: white;
-	  border-radius: 20px;
-	  text-align: center;
-	  font: bold 14px "Helvetica Neue", Sans-Serif;
-	  font-stretch: condensed;
-	  text-decoration: none;
-	  text-transform: uppercase;
-	  box-shadow: 0 0 7px black;
+		padding: 10px 20px;
+		color: white;
+		border-radius: 20px;
+		font: bold 14px "Helvetica Neue", Sans-Serif;
+		text-transform: uppercase;
+		box-shadow: 0 0 7px black;
 	}
 	.arrow {
-	    width: 70px;
-	    height: 16px;
-	    overflow: hidden;
-	    position: absolute;
-	    left: 50%;
-	    margin-left: -35px;
-	    bottom: -16px;
+		width: 70px;
+		height: 16px;
+		overflow: hidden;
+		position: absolute;
+		left: 50%;
+		margin-left: -35px;
+		bottom: -16px;
+	}
+	.arrow.top {
+		top: -16px;
+		bottom: auto;
+	}
+	.arrow.left {
+		left: 20%;
 	}
 	.arrow:after {
-	  content: "";
-	  position: absolute;
-	  left: 20px;
-	  top: -20px;
-	  width: 25px;
-	  height: 25px;
-	  -webkit-box-shadow: 6px 5px 9px -9px black,
-	              5px 6px 9px -9px black;
-	  -moz-box-shadow: 6px 5px 9px -9px black,
-	              5px 6px 9px -9px black;
-	  box-shadow: 6px 5px 9px -9px black,
-	              5px 6px 9px -9px black;
-	  -webkit-transform: rotate(45deg);
-	  -moz-transform:    rotate(45deg);
-	  -ms-transform:     rotate(45deg);
-	  -o-transform:      rotate(45deg);
+		content: "";
+		position: absolute;
+		left: 20px;
+		top: -20px;
+		width: 25px;
+		height: 25px;
+		box-shadow: 6px 5px 9px -9px black;
+		-webkit-transform: rotate(45deg);
+		-moz-transform: rotate(45deg);
+		-ms-transform: rotate(45deg);
+		-o-transform: rotate(45deg);
+		tranform: rotate(45deg);
 	}
-	div[data-tooltip].active {
-	  opacity: 1;
-	  margin-top: 6px;
-	}
-	div[data-tooltip].out {
-	  opacity: 0;
-	  margin-top: -20px;
+	.arrow.top:after {
+		bottom: -20px;
+		top: auto;
 	}
 	</style>
 </head>
diff --git a/tests/unit/position/position.html b/tests/unit/position/position.html
index 518e1f960..2a6e43d36 100644
--- a/tests/unit/position/position.html
+++ b/tests/unit/position/position.html
@@ -43,7 +43,7 @@ elements smaller than 10px have a line-height set on them to avoid a bug in IE6
 	<div id="parent" style="position: absolute; width: 6px; height: 6px; top: 4px; left: 4px; line-height: 6px;"></div>
 	<div id="within" style="position: absolute; width: 12px; height: 12px; top: 2px; left: 0px;"></div>
 
-	<div style="position: absolute; top: 0px; left: 0px">
+	<div id="scrollx" style="position: absolute; top: 0px; left: 0px">
 		<div id="elx" style="position: absolute; width: 10px; height: 10px; line-height: 10px;"></div>
 		<div id="parentx" style="position: absolute; width: 20px; height: 20px; top: 40px; left: 40px;"></div>
 	</div>
diff --git a/tests/unit/position/position_core.js b/tests/unit/position/position_core.js
index 837327b5d..e68e310f1 100644
--- a/tests/unit/position/position_core.js
+++ b/tests/unit/position/position_core.js
@@ -255,11 +255,30 @@ test( "offsets", function() {
 });
 
 test( "using", function() {
-	expect( 6 );
+	expect( 10 );
 
 	var count = 0,
 		elems = $( "#el1, #el2" ),
-		expectedPosition = { top: 40, left: 40 },
+		of = $( "#parentx" ),
+		expectedPosition = { top: 60, left: 60 },
+		expectedFeedback = {
+			target: {
+				element: of,
+				width: 20,
+				height: 20,
+				left: 40,
+				top: 40
+			},
+			element: {
+				width: 6,
+				height: 6,
+				left: 60,
+				top: 60
+			},
+			horizontal: "left",
+			vertical: "top",
+			important: "vertical"
+		},
 		originalPosition = elems.position({
 			my: "right bottom",
 			at: "rigt bottom",
@@ -269,11 +288,14 @@ test( "using", function() {
 
 	elems.position({
 		my: "left top",
-		at: "left top",
+		at: "center+10 bottom",
 		of: "#parentx",
-		using: function( position ) {
+		using: function( position, feedback ) {
 			deepEqual( this, elems[ count ], "correct context for call #" + count );
 			deepEqual( position, expectedPosition, "correct position for call #" + count );
+			deepEqual( feedback.element.element[ 0 ], elems[ count ] );
+			delete feedback.element.element;
+			deepEqual( feedback, expectedFeedback );
 			count++;
 		}
 	});
@@ -569,6 +591,67 @@ test( "within", function() {
 	}, "flipfit - left top" );
 });
 
+test( "with scrollbars", function() {
+	expect( 4 );
+
+	$( "#scrollx" ).css({
+		width: 100,
+		height: 100,
+		left: 0,
+		top: 0
+	});
+
+	collisionTest({
+		of: "#scrollx",
+		collision: "fit",
+		within: "#scrollx"
+	}, {
+		top: 90,
+		left: 90
+	}, "visible" );
+
+	$( "#scrollx" ).css({
+		overflow: "scroll"
+	});
+
+	var scrollbarInfo = $.position.getScrollInfo( $.position.getWithinInfo( $( "#scrollx" ) ) );
+
+	collisionTest({
+		of: "#scrollx",
+		collision: "fit",
+		within: "#scrollx"
+	}, {
+		top: 90 - scrollbarInfo.height,
+		left: 90 - scrollbarInfo.width
+	}, "scroll" );
+
+	$( "#scrollx" ).css({
+		overflow: "auto"
+	});
+
+	collisionTest({
+		of: "#scrollx",
+		collision: "fit",
+		within: "#scrollx"
+	}, {
+		top: 90,
+		left: 90
+	}, "auto, no scroll" );
+
+	$( "#scrollx" ).css({
+		overflow: "auto"
+	}).append( $("<div>").height(300).width(300) );
+
+	collisionTest({
+		of: "#scrollx",
+		collision: "fit",
+		within: "#scrollx"
+	}, {
+		top: 90 - scrollbarInfo.height,
+		left: 90 - scrollbarInfo.width
+	}, "auto, with scroll" );
+});
+
 test( "fractions", function() {
 	expect( 1 );
 
diff --git a/tests/visual/position/position.html b/tests/visual/position/position.html
index b9b769d9b..64c5d2300 100644
--- a/tests/visual/position/position.html
+++ b/tests/visual/position/position.html
@@ -10,23 +10,31 @@
 	<script type="text/javascript" src="../../../ui/jquery.ui.widget.js"></script>
 	<script type="text/javascript" src="../../../ui/jquery.ui.position.js"></script>
 	<script type="text/javascript" src="../../../ui/jquery.ui.menu.js"></script>
-	<script type="text/javascript" src="http://jqueryui.com/themeroller/themeswitchertool/"></script>
 	<script type="text/javascript">
 	$(function() {
 		var inputs = $("input");
 		$("ul").insertAfter(inputs);
 		$(window).resize(function() {
 			inputs.each(function() {
-				$(this).position({
+				var input = $(this).position({
 					my: this.id.replace(/-/, " "),
 					at: this.id.replace(/-/, " "),
 					of: "#container",
 					collision: "none"
 				});
-				$(this).next().menu().position({
-					my: "left top+20",
+				var menu = $(this).next().menu()
+				menu.position({
+					my: "left+30 top+20",
 					at: "left bottom",
 					of: this,
+					using: function( position, feedback ) {
+						input.val(feedback.horizontal + " " + feedback.vertical)
+						$(this).offset( position );
+						$(this)
+							.removeClass("left right top bottom center middle")
+							.addClass(feedback.horizontal)
+							.addClass(feedback.vertical);
+					}
 				});
 			});
 		}).resize();
@@ -44,11 +52,11 @@
 			top: -22px;
 			left: 5px;
 		}
-		.ui-flipped-left:before {
+		.right:before {
 			left: auto;
 			right: 5px;
 		}
-		.ui-flipped-top:before {
+		.bottom:before {
 			content: "↓";
 			top: auto;
 			bottom: -19px;
diff --git a/tests/visual/position/position_feedback.html b/tests/visual/position/position_feedback.html
new file mode 100644
index 000000000..006a1be02
--- /dev/null
+++ b/tests/visual/position/position_feedback.html
@@ -0,0 +1,146 @@
+<!doctype html>
+<html lang="en">
+<head>
+	<meta charset="utf-8">
+	<title>Position Visual Test: Default</title>
+	<link rel="stylesheet" href="../visual.css">
+	<link rel="stylesheet" href="../../../themes/base/jquery.ui.all.css">
+	<script src="../../../jquery-1.7.2.js"></script>
+	<script src="../../../ui/jquery.ui.core.js"></script>
+	<script src="../../../ui/jquery.ui.widget.js"></script>
+	<script src="../../../ui/jquery.ui.position.js"></script>
+	<script src="../../../ui/jquery.ui.menu.js"></script>
+	<script>
+	$(function() {
+		function using( position, feedback ) {
+			$( this )
+				.css( position )
+				.text( feedback.horizontal + " " + feedback.vertical + " " + feedback.important )
+				.removeClass( "left right top bottom center middle vertical horizontal" )
+				.addClass( feedback.horizontal )
+				.addClass( feedback.vertical )
+				.addClass( feedback.important );
+		}
+
+		var element = $( ".element" ),
+			target = $( "#target" ).position({
+				my: "center",
+				at: "center",
+				of: window
+			}),
+			targetOffset = target.offset(),
+			oppositeElement = element.clone().width( 50 ).appendTo( "body" ),
+			leftElement = element.clone().width( 50 ).height( 150 ).appendTo( "body" ),
+			rightElement = element.clone().height( 150 ).width( 150 ).appendTo( "body" );
+
+		$.each([
+			"center top-100",
+			"right+25 top-50",
+			"right+75 top",
+			"right+75 center",
+			"right+75 bottom",
+			"right+25 bottom+50",
+			"center bottom+100",
+			"left-25 bottom+50",
+			"left-75 bottom",
+			"left-75 center",
+			"left-75 top",
+			"left-25 top-50"
+		], function( index, direction ) {
+			element.clone().insertAfter( target ).position({
+				my: "center",
+				at: direction,
+				of: target,
+				using: using
+			});
+		});
+
+		element.width( 150 );
+		$( document ).on( "mousemove", function( event ) {
+			var base = {
+				my: "left top",
+				at: "left top",
+				of: target,
+				using: using
+			};
+			element.position( $.extend({
+				offset: (event.pageX - targetOffset.left) + " " + (event.pageY - targetOffset.top)
+			}, base ));
+			oppositeElement.position( $.extend({
+				offset: (-1 * (event.pageX - targetOffset.left)) + " " + (-1 * (event.pageY - targetOffset.top))
+			}, base ));
+			leftElement.position( $.extend({
+				offset: (-0.9 * (event.pageX - targetOffset.left)) + " " + (0.9 * (event.pageY - targetOffset.top))
+			}, base ));
+			rightElement.position( $.extend({
+				offset: (0.9 * (event.pageX - targetOffset.left)) + " " + (-0.9 * (event.pageY - targetOffset.top))
+			}, base) );
+		});
+	});
+	</script>
+	<style>
+	#target, .element {
+		position: absolute;
+		border: 1px solid black;
+		border-radius: 5px;
+		width: 75px;
+		height: 25px;
+		padding: 5px;
+	}
+	#target {
+		height: 75px;
+	}
+	.element:before {
+		font-size: 12pt;
+		content: "↑";
+		position: absolute;
+		top: -19px;
+		left: 5px;
+	}
+	.right:before {
+		left: auto;
+		right: 5px;
+	}
+	.bottom:before {
+		content: "↓";
+		top: auto;
+		bottom: -19px;
+	}
+	.center:before {
+		left: 50%;
+		right: auto;
+	}
+	.middle:before {
+		top: 50%;
+		bottom: auto;
+	}
+	.horizontal:before {
+		height: 10px;
+		top: 50%;
+		margin-top: -8px;
+		bottom: auto;
+		left: -18px;
+		right: auto;
+		content: "←";
+	}
+	.right.horizontal:before {
+		left: auto;
+		right: -18px;
+		content: "→";
+	}
+	.bottom.horizontal:before {
+		top: auto;
+		bottom: 5px;
+	}
+	.top.horizontal:before {
+		top: 5px;
+	}
+	</style>
+</head>
+<body>
+
+<div id="target">all around me</div>
+<div class="element"></div>
+
+</body>
+</html>
diff --git a/tests/visual/position/position_feedback_rotate.html b/tests/visual/position/position_feedback_rotate.html
new file mode 100644
index 000000000..11138b112
--- /dev/null
+++ b/tests/visual/position/position_feedback_rotate.html
@@ -0,0 +1,109 @@
+<!doctype html>
+<html lang="en">
+<head>
+	<meta charset="utf-8">
+	<title>Position Visual Test: Default</title>
+	<link rel="stylesheet" href="../visual.css">
+	<link rel="stylesheet" href="../../../themes/base/jquery.ui.all.css">
+	<script src="../../../jquery-1.7.2.js"></script>
+	<script src="../../../ui/jquery.ui.core.js"></script>
+	<script src="../../../ui/jquery.ui.widget.js"></script>
+	<script src="../../../ui/jquery.ui.position.js"></script>
+	<script src="../../../ui/jquery.ui.menu.js"></script>
+	<script>
+	$(function() {
+		function using( position, feedback ) {
+			var angleRad = Math.atan2(
+					feedback.target.top + feedback.target.height / 2 - feedback.element.top - feedback.element.height / 2,
+					feedback.target.left + feedback.target.width / 2 - feedback.element.left - feedback.element.width / 2
+				) * 180 / Math.PI,
+				angle = Math.round( angleRad * 100) / 100;
+			$( this )
+				.css( position )
+				.text( feedback.horizontal + " " + feedback.vertical + " " + feedback.important + " " + angle + "°" )
+				.css({
+					"-webkit-transform": "rotate(" + angle + "deg)",
+					"-moz-transform": "rotate(" + angle + "deg)",
+					"-ms-transform": "rotate(" + angle + "deg)",
+					"-o-transform": "rotate(" + angle + "deg)",
+					"transform": "rotate(" + angle + "deg)"
+				});
+		}
+
+		var element = $( ".element" ),
+			target = $( "#target" ).position({
+				my: "center",
+				at: "center",
+				of: window
+			}),
+			targetOffset = target.offset();
+			oppositeElement = element.clone().width( 50 ).appendTo( "body" ),
+			leftElement = element.clone().width( 50 ).height( 150 ).appendTo( "body" ),
+			rightElement = element.clone().height( 150 ).width( 150 ).appendTo( "body" );
+
+		$.each([
+			"center top-100",
+			"right+25 top-50",
+			"right+75 top",
+			"right+75 center",
+			"right+75 bottom",
+			"right+25 bottom+50",
+			"center bottom+100",
+			"left-25 bottom+50",
+			"left-75 bottom",
+			"left-75 center",
+			"left-75 top",
+			"left-25 top-50"
+		], function( index, direction ) {
+			element.clone().insertAfter( target ).position({
+				my: "center",
+				at: direction,
+				of: target,
+				using: using
+			});
+		});
+
+		element.width( 150 );
+		$( document ).on( "mousemove", function( event ) {
+			var base = {
+				my: "left top",
+				at: "left top",
+				of: target,
+				using: using
+			};
+			element.position( $.extend({
+				offset: (event.pageX - targetOffset.left) + " " + (event.pageY - targetOffset.top)
+			}, base ));
+			oppositeElement.position( $.extend({
+				offset: (-1 * (event.pageX - targetOffset.left)) + " " + (-1 * (event.pageY - targetOffset.top))
+			}, base ));
+			leftElement.position( $.extend({
+				offset: (-0.9 * (event.pageX - targetOffset.left)) + " " + (0.9 * (event.pageY - targetOffset.top))
+			}, base ));
+			rightElement.position( $.extend({
+				offset: (0.9 * (event.pageX - targetOffset.left)) + " " + (-0.9 * (event.pageY - targetOffset.top))
+			}, base ));
+		});
+	});
+	</script>
+	<style>
+	#target, .element {
+		position: absolute;
+		border: 1px solid black;
+		border-radius: 5px;
+		width: 75px;
+		height: 25px;
+		padding: 5px;
+	}
+	#target {
+		height: 75px;
+	}
+	</style>
+</head>
+<body>
+
+<div id="target">all around me</div>
+<div class="element"></div>
+
+</body>
+</html>
diff --git a/tests/visual/position/position_fit.html b/tests/visual/position/position_fit.html
index 9c60b78f6..dbd52550f 100644
--- a/tests/visual/position/position_fit.html
+++ b/tests/visual/position/position_fit.html
@@ -10,7 +10,6 @@
 	<script type="text/javascript" src="../../../ui/jquery.ui.widget.js"></script>
 	<script type="text/javascript" src="../../../ui/jquery.ui.position.js"></script>
 	<script type="text/javascript" src="../../../ui/jquery.ui.menu.js"></script>
-	<script type="text/javascript" src="http://jqueryui.com/themeroller/themeswitchertool/"></script>
 	<script type="text/javascript">
 	$(function() {
 		var inputs = $("input");
diff --git a/tests/visual/position/position_flip.html b/tests/visual/position/position_flip.html
index bae3c649b..29ad32f96 100644
--- a/tests/visual/position/position_flip.html
+++ b/tests/visual/position/position_flip.html
@@ -10,7 +10,6 @@
 	<script type="text/javascript" src="../../../ui/jquery.ui.widget.js"></script>
 	<script type="text/javascript" src="../../../ui/jquery.ui.position.js"></script>
 	<script type="text/javascript" src="../../../ui/jquery.ui.menu.js"></script>
-	<script type="text/javascript" src="http://jqueryui.com/themeroller/themeswitchertool/"></script>
 	<script type="text/javascript">
 	$(function() {
 		var inputs = $("input");
diff --git a/tests/visual/position/position_flipfit.html b/tests/visual/position/position_flipfit.html
index fcfb75b6b..fb99e4007 100644
--- a/tests/visual/position/position_flipfit.html
+++ b/tests/visual/position/position_flipfit.html
@@ -10,7 +10,6 @@
 	<script type="text/javascript" src="../../../ui/jquery.ui.widget.js"></script>
 	<script type="text/javascript" src="../../../ui/jquery.ui.position.js"></script>
 	<script type="text/javascript" src="../../../ui/jquery.ui.menu.js"></script>
-	<script type="text/javascript" src="http://jqueryui.com/themeroller/themeswitchertool/"></script>
 	<script type="text/javascript">
 	$(function() {
 		var inputs = $("input");
diff --git a/tests/visual/position/position_margin.html b/tests/visual/position/position_margin.html
index 71d8f0a3c..2e3b63266 100644
--- a/tests/visual/position/position_margin.html
+++ b/tests/visual/position/position_margin.html
@@ -9,7 +9,6 @@
 	<script type="text/javascript" src="../../../ui/jquery.ui.core.js"></script>
 	<script type="text/javascript" src="../../../ui/jquery.ui.widget.js"></script>
 	<script type="text/javascript" src="../../../ui/jquery.ui.position.js"></script>
-	<script type="text/javascript" src="http://jqueryui.com/themeroller/themeswitchertool/"></script>
 	<script type="text/javascript">
 	$(function() {
 		$( "#elem" ).position({
diff --git a/tests/visual/position/position_within.html b/tests/visual/position/position_within.html
index 7d8813582..692cb1067 100644
--- a/tests/visual/position/position_within.html
+++ b/tests/visual/position/position_within.html
@@ -97,7 +97,7 @@
                     collision: $( "#collision_horizontal" ).val() + " " + $( "#collision_vertical" ).val()
                 });
             }
-            $( ".demo" ).append("<div style='width:5000px;height:5000px;' />").css("overflow","auto");
+            $( ".demo" ).css("overflow","scroll");
 
             $( ".positionable" ).css( "opacity", 0.5 );
 
diff --git a/themes/base/jquery.ui.tooltip.css b/themes/base/jquery.ui.tooltip.css
index f1fa50cc6..d144b0a7f 100644
--- a/themes/base/jquery.ui.tooltip.css
+++ b/themes/base/jquery.ui.tooltip.css
@@ -4,8 +4,6 @@
  * Copyright 2012, AUTHORS.txt (http://jqueryui.com/about)
  * Dual licensed under the MIT or GPL Version 2 licenses.
  * http://jquery.org/license
- *
- * http://docs.jquery.com/UI/Tooltip#theming
  */
 .ui-tooltip {
 	padding:8px;
diff --git a/ui/jquery.ui.position.js b/ui/jquery.ui.position.js
index 95b8b460d..d4d09bee4 100644
--- a/ui/jquery.ui.position.js
+++ b/ui/jquery.ui.position.js
@@ -11,16 +11,32 @@
 
 $.ui = $.ui || {};
 
-var rhorizontal = /left|center|right/,
+var cachedScrollbarWidth,
+	max = Math.max,
+	abs = Math.abs,
+	round = Math.round,
+	rhorizontal = /left|center|right/,
 	rvertical = /top|center|bottom/,
 	roffset = /[\+\-]\d+%?/,
 	rposition = /^\w+/,
 	rpercent = /%$/,
-	center = "center",
 	_position = $.fn.position;
 
+function getOffsets( offsets, width, height ) {
+	return [
+		parseInt( offsets[ 0 ], 10 ) * ( rpercent.test( offsets[ 0 ] ) ? width / 100 : 1 ),
+		parseInt( offsets[ 1 ], 10 ) * ( rpercent.test( offsets[ 1 ] ) ? height / 100 : 1 )
+	];
+}
+function parseCss( element, property ) {
+	return parseInt( $.css( element, property ), 10 ) || 0;
+}
+
 $.position = {
 	scrollbarWidth: function() {
+		if ( cachedScrollbarWidth !== undefined ) {
+			return cachedScrollbarWidth;
+		}
 		var w1, w2,
 			div = $( "<div style='display:block;width:50px;height:50px;overflow:hidden;'><div style='height:100px;width:auto;'></div></div>" ),
 			innerDiv = div.children()[0];
@@ -37,18 +53,31 @@ $.position = {
 
 		div.remove();
 
-		return w1 - w2;
+		return (cachedScrollbarWidth = w1 - w2);
 	},
-	getScrollInfo: function(within) {
-		var notWindow = within[0] !== window,
-			overflowX = notWindow ? within.css( "overflow-x" ) : "",
-			overflowY = notWindow ? within.css( "overflow-y" ) : "",
-			scrollbarWidth = overflowX === "auto" || overflowX === "scroll" ? $.position.scrollbarWidth() : 0,
-			scrollbarHeight = overflowY === "auto" || overflowY === "scroll" ? $.position.scrollbarWidth() : 0;
-
+	getScrollInfo: function( within ) {
+		var overflowX = within.isWindow ? "" : within.element.css( "overflow-x" ),
+			overflowY = within.isWindow ? "" : within.element.css( "overflow-y" ),
+			hasOverflowX = overflowX === "scroll" ||
+				( overflowX === "auto" && within.width < within.element[0].scrollWidth ),
+			hasOverflowY = overflowY === "scroll" ||
+				( overflowY === "auto" && within.height < within.element[0].scrollHeight );
 		return {
-			height: within.height() < within[0].scrollHeight ? scrollbarHeight : 0,
-			width: within.width() < within[0].scrollWidth ? scrollbarWidth : 0
+			width: hasOverflowX ? $.position.scrollbarWidth() : 0,
+			height: hasOverflowY ? $.position.scrollbarWidth() : 0
+		};
+	},
+	getWithinInfo: function( element ) {
+		var withinElement = $( element || window ),
+			isWindow = $.isWindow( withinElement[0] );
+		return {
+			element: withinElement,
+			isWindow: isWindow,
+			offset: withinElement.offset() || { left: 0, top: 0 },
+			scrollLeft: withinElement.scrollLeft(),
+			scrollTop: withinElement.scrollTop(),
+			width: isWindow ? withinElement.width() : withinElement.outerWidth(),
+			height: isWindow ? withinElement.height() : withinElement.outerHeight()
 		};
 	}
 };
@@ -61,34 +90,34 @@ $.fn.position = function( options ) {
 	// make a copy, we don't want to modify arguments
 	options = $.extend( {}, options );
 
-	var target = $( options.of ),
-		within  = $( options.within || window ),
+	var atOffset, targetWidth, targetHeight, targetOffset, basePosition,
+		target = $( options.of ),
+		within = $.position.getWithinInfo( options.within ),
+		scrollInfo = $.position.getScrollInfo( within ),
 		targetElem = target[0],
 		collision = ( options.collision || "flip" ).split( " " ),
-		offsets = {},
-		atOffset,
-		targetWidth,
-		targetHeight,
-		basePosition;
+		offsets = {};
 
 	if ( targetElem.nodeType === 9 ) {
 		targetWidth = target.width();
 		targetHeight = target.height();
-		basePosition = { top: 0, left: 0 };
+		targetOffset = { top: 0, left: 0 };
 	} else if ( $.isWindow( targetElem ) ) {
 		targetWidth = target.width();
 		targetHeight = target.height();
-		basePosition = { top: target.scrollTop(), left: target.scrollLeft() };
+		targetOffset = { top: target.scrollTop(), left: target.scrollLeft() };
 	} else if ( targetElem.preventDefault ) {
 		// force left top to allow flipping
 		options.at = "left top";
 		targetWidth = targetHeight = 0;
-		basePosition = { top: options.of.pageY, left: options.of.pageX };
+		targetOffset = { top: targetElem.pageY, left: targetElem.pageX };
 	} else {
 		targetWidth = target.outerWidth();
 		targetHeight = target.outerHeight();
-		basePosition = target.offset();
+		targetOffset = target.offset();
 	}
+	// clone to reuse original targetOffset later
+	basePosition = $.extend( {}, targetOffset );
 
 	// force my and at to have valid horizontal and vertical positions
 	// if a value is missing or invalid, it will be converted to center
@@ -99,13 +128,13 @@ $.fn.position = function( options ) {
 
 		if ( pos.length === 1) {
 			pos = rhorizontal.test( pos[ 0 ] ) ?
-				pos.concat( [ center ] ) :
+				pos.concat( [ "center" ] ) :
 				rvertical.test( pos[ 0 ] ) ?
-					[ center ].concat( pos ) :
-					[ center, center ];
+					[ "center" ].concat( pos ) :
+					[ "center", "center" ];
 		}
-		pos[ 0 ] = rhorizontal.test( pos[ 0 ] ) ? pos[ 0 ] : center;
-		pos[ 1 ] = rvertical.test( pos[ 1 ] ) ? pos[ 1 ] : center;
+		pos[ 0 ] = rhorizontal.test( pos[ 0 ] ) ? pos[ 0 ] : "center";
+		pos[ 1 ] = rvertical.test( pos[ 1 ] ) ? pos[ 1 ] : "center";
 
 		// calculate offsets
 		horizontalOffset = roffset.exec( pos[ 0 ] );
@@ -129,54 +158,41 @@ $.fn.position = function( options ) {
 
 	if ( options.at[ 0 ] === "right" ) {
 		basePosition.left += targetWidth;
-	} else if ( options.at[ 0 ] === center ) {
+	} else if ( options.at[ 0 ] === "center" ) {
 		basePosition.left += targetWidth / 2;
 	}
 
 	if ( options.at[ 1 ] === "bottom" ) {
 		basePosition.top += targetHeight;
-	} else if ( options.at[ 1 ] === center ) {
+	} else if ( options.at[ 1 ] === "center" ) {
 		basePosition.top += targetHeight / 2;
 	}
 
-	atOffset = [
-		parseInt( offsets.at[ 0 ], 10 ) *
-			( rpercent.test( offsets.at[ 0 ] ) ? targetWidth / 100 : 1 ),
-		parseInt( offsets.at[ 1 ], 10 ) *
-			( rpercent.test( offsets.at[ 1 ] ) ? targetHeight / 100 : 1 )
-	];
+	atOffset = getOffsets( offsets.at, targetWidth, targetHeight );
 	basePosition.left += atOffset[ 0 ];
 	basePosition.top += atOffset[ 1 ];
 
 	return this.each(function() {
-		var elem = $( this ),
+		var collisionPosition, using,
+			elem = $( this ),
 			elemWidth = elem.outerWidth(),
 			elemHeight = elem.outerHeight(),
-			marginLeft = parseInt( $.css( this, "marginLeft" ), 10 ) || 0,
-			marginTop = parseInt( $.css( this, "marginTop" ), 10 ) || 0,
-			scrollInfo = $.position.getScrollInfo( within ),
-			collisionWidth = elemWidth + marginLeft +
-				( parseInt( $.css( this, "marginRight" ), 10 ) || 0 ) + scrollInfo.width,
-			collisionHeight = elemHeight + marginTop +
-				( parseInt( $.css( this, "marginBottom" ), 10 ) || 0 ) + scrollInfo.height,
+			marginLeft = parseCss( this, "marginLeft" ),
+			marginTop = parseCss( this, "marginTop" ),
+			collisionWidth = elemWidth + marginLeft + parseCss( this, "marginRight" ) + scrollInfo.width,
+			collisionHeight = elemHeight + marginTop + parseCss( this, "marginBottom" ) + scrollInfo.height,
 			position = $.extend( {}, basePosition ),
-			myOffset = [
-				parseInt( offsets.my[ 0 ], 10 ) *
-					( rpercent.test( offsets.my[ 0 ] ) ? elem.outerWidth() / 100 : 1 ),
-				parseInt( offsets.my[ 1 ], 10 ) *
-					( rpercent.test( offsets.my[ 1 ] ) ? elem.outerHeight() / 100 : 1 )
-			],
-			collisionPosition;
+			myOffset = getOffsets( offsets.my, elem.outerWidth(), elem.outerHeight() );
 
 		if ( options.my[ 0 ] === "right" ) {
 			position.left -= elemWidth;
-		} else if ( options.my[ 0 ] === center ) {
+		} else if ( options.my[ 0 ] === "center" ) {
 			position.left -= elemWidth / 2;
 		}
 
 		if ( options.my[ 1 ] === "bottom" ) {
 			position.top -= elemHeight;
-		} else if ( options.my[ 1 ] === center ) {
+		} else if ( options.my[ 1 ] === "center" ) {
 			position.top -= elemHeight / 2;
 		}
 
@@ -185,8 +201,8 @@ $.fn.position = function( options ) {
 
 		// if the browser doesn't support fractions, then round for consistent results
 		if ( !$.support.offsetFractions ) {
-			position.left = Math.round( position.left );
-			position.top = Math.round( position.top );
+			position.left = round( position.left );
+			position.top = round( position.top );
 		}
 
 		collisionPosition = {
@@ -216,7 +232,48 @@ $.fn.position = function( options ) {
 		if ( $.fn.bgiframe ) {
 			elem.bgiframe();
 		}
-		elem.offset( $.extend( position, { using: options.using } ) );
+
+		if ( options.using ) {
+			// adds feedback as second argument to using callback, if present
+			using = function( props ) {
+				var left = targetOffset.left - position.left,
+					right = left + targetWidth - elemWidth,
+					top = targetOffset.top - position.top,
+					bottom = top + targetHeight - elemHeight,
+					feedback = {
+						target: {
+							element: target,
+							left: targetOffset.left,
+							top: targetOffset.top,
+							width: targetWidth,
+							height: targetHeight
+						},
+						element: {
+							element: elem,
+							left: position.left,
+							top: position.top,
+							width: elemWidth,
+							height: elemHeight
+						},
+						horizontal: right < 0 ? "left" : left > 0 ? "right" : "center",
+						vertical: bottom < 0 ? "top" : top > 0 ? "bottom" : "middle"
+					};
+				if ( targetWidth < elemWidth && abs( left + right ) < targetWidth ) {
+					feedback.horizontal = "center";
+				}
+				if ( targetHeight < elemHeight && abs( top + bottom ) < targetHeight ) {
+					feedback.vertical = "middle";
+				}
+				if ( max( abs( left ), abs( right ) ) > max( abs( top ), abs( bottom ) ) ) {
+					feedback.important = "horizontal";
+				} else {
+					feedback.important = "vertical";
+				}
+				options.using.call( this, props, feedback );
+			};
+		}
+
+		elem.offset( $.extend( position, { using: using } ) );
 	});
 };
 
@@ -224,10 +281,8 @@ $.ui.position = {
 	fit: {
 		left: function( position, data ) {
 			var within = data.within,
-				win = $( window ),
-				isWindow = $.isWindow( data.within[0] ),
-				withinOffset = isWindow ? win.scrollLeft() : within.offset().left,
-				outerWidth = isWindow ? win.width() : within.outerWidth(),
+				withinOffset = within.isWindow ? within.scrollLeft : within.offset.left,
+				outerWidth = within.width,
 				collisionPosLeft = position.left - data.collisionPosition.marginLeft,
 				overLeft = withinOffset - collisionPosLeft,
 				overRight = collisionPosLeft + data.collisionWidth - outerWidth - withinOffset,
@@ -259,15 +314,13 @@ $.ui.position = {
 				position.left -= overRight;
 			// adjust based on position and margin
 			} else {
-				position.left = Math.max( position.left - collisionPosLeft, position.left );
+				position.left = max( position.left - collisionPosLeft, position.left );
 			}
 		},
 		top: function( position, data ) {
 			var within = data.within,
-				win = $( window ),
-				isWindow = $.isWindow( data.within[0] ),
-				withinOffset = isWindow ? win.scrollTop() : within.offset().top,
-				outerHeight = isWindow ? win.height() : within.outerHeight(),
+				withinOffset = within.isWindow ? within.scrollTop : within.offset.top,
+				outerHeight = data.within.height,
 				collisionPosTop = position.top - data.collisionPosition.marginTop,
 				overTop = withinOffset - collisionPosTop,
 				overBottom = collisionPosTop + data.collisionHeight - outerHeight - withinOffset,
@@ -299,25 +352,20 @@ $.ui.position = {
 				position.top -= overBottom;
 			// adjust based on position and margin
 			} else {
-				position.top = Math.max( position.top - collisionPosTop, position.top );
+				position.top = max( position.top - collisionPosTop, position.top );
 			}
 		}
 	},
 	flip: {
 		left: function( position, data ) {
-			if ( data.at[ 0 ] === center ) {
+			if ( data.at[ 0 ] === "center" ) {
 				return;
 			}
 
-			data.elem
-				.removeClass( "ui-flipped-left ui-flipped-right" );
-
 			var within = data.within,
-				win = $( window ),
-				isWindow = $.isWindow( data.within[0] ),
-				withinOffset = ( isWindow ? 0 : within.offset().left ) + within.scrollLeft(),
-				outerWidth = isWindow ? within.width() : within.outerWidth(),
-				offsetLeft = isWindow ? 0 : within.offset().left,
+				withinOffset = within.offset.left + within.scrollLeft,
+				outerWidth = within.width,
+				offsetLeft = within.isWindow ? 0 : within.offset.left,
 				collisionPosLeft = position.left - data.collisionPosition.marginLeft,
 				overLeft = collisionPosLeft - offsetLeft,
 				overRight = collisionPosLeft + data.collisionWidth - outerWidth - offsetLeft,
@@ -336,37 +384,26 @@ $.ui.position = {
 
 			if ( overLeft < 0 ) {
 				newOverRight = position.left + myOffset + atOffset + offset + data.collisionWidth - outerWidth - withinOffset;
-				if ( newOverRight < 0 || newOverRight < Math.abs( overLeft ) ) {
-					data.elem
-						.addClass( "ui-flipped-right" );
-
+				if ( newOverRight < 0 || newOverRight < abs( overLeft ) ) {
 					position.left += myOffset + atOffset + offset;
 				}
 			}
 			else if ( overRight > 0 ) {
 				newOverLeft = position.left - data.collisionPosition.marginLeft + myOffset + atOffset + offset - offsetLeft;
-				if ( newOverLeft > 0 || Math.abs( newOverLeft ) < overRight ) {
-					data.elem
-						.addClass( "ui-flipped-left" );
-
+				if ( newOverLeft > 0 || abs( newOverLeft ) < overRight ) {
 					position.left += myOffset + atOffset + offset;
 				}
 			}
 		},
 		top: function( position, data ) {
-			if ( data.at[ 1 ] === center ) {
+			if ( data.at[ 1 ] === "center" ) {
 				return;
 			}
 
-			data.elem
-				.removeClass( "ui-flipped-top ui-flipped-bottom" );
-
 			var within = data.within,
-				win = $( window ),
-				isWindow = $.isWindow( data.within[0] ),
-				withinOffset = ( isWindow ? 0 : within.offset().top ) + within.scrollTop(),
-				outerHeight = isWindow ? within.height() : within.outerHeight(),
-				offsetTop = isWindow ? 0 : within.offset().top,
+				withinOffset = within.offset.top + within.scrollTop,
+				outerHeight = within.height,
+				offsetTop = within.isWindow ? 0 : within.offset.top,
 				collisionPosTop = position.top - data.collisionPosition.marginTop,
 				overTop = collisionPosTop - offsetTop,
 				overBottom = collisionPosTop + data.collisionHeight - outerHeight - offsetTop,
@@ -384,19 +421,13 @@ $.ui.position = {
 				newOverBottom;
 			if ( overTop < 0 ) {
 				newOverBottom = position.top + myOffset + atOffset + offset + data.collisionHeight - outerHeight - withinOffset;
-				if ( ( position.top + myOffset + atOffset + offset) > overTop && ( newOverBottom < 0 || newOverBottom < Math.abs( overTop ) ) ) {
-					data.elem
-						.addClass( "ui-flipped-bottom" );
-
+				if ( ( position.top + myOffset + atOffset + offset) > overTop && ( newOverBottom < 0 || newOverBottom < abs( overTop ) ) ) {
 					position.top += myOffset + atOffset + offset;
 				}
 			}
 			else if ( overBottom > 0 ) {
 				newOverTop = position.top -  data.collisionPosition.marginTop + myOffset + atOffset + offset - offsetTop;
-				if ( ( position.top + myOffset + atOffset + offset) > overBottom && ( newOverTop > 0 || Math.abs( newOverTop ) < overBottom ) ) {
-					data.elem
-						.addClass( "ui-flipped-top" );
-
+				if ( ( position.top + myOffset + atOffset + offset) > overBottom && ( newOverTop > 0 || abs( newOverTop ) < overBottom ) ) {
 					position.top += myOffset + atOffset + offset;
 				}
 			}
diff --git a/ui/jquery.ui.tooltip.js b/ui/jquery.ui.tooltip.js
index 97895a6a8..424eca7af 100644
--- a/ui/jquery.ui.tooltip.js
+++ b/ui/jquery.ui.tooltip.js
@@ -5,8 +5,6 @@
  * Dual licensed under the MIT or GPL Version 2 licenses.
  * http://jquery.org/license
  *
- * http://docs.jquery.com/UI/Tooltip
- *
  * Depends:
  *	jquery.ui.core.js
  *	jquery.ui.widget.js