Sortable - Tolerance accuracy sortable improved

1 files changed, 255 insertions, 239 deletions

diff --git a/ui/ui.sortable.js b/ui/ui.sortable.js
index 5fa9e4f3b..4178cdcd6 100644
--- a/ui/ui.sortable.js
+++ b/ui/ui.sortable.js
@@ -4,7 +4,7 @@
  * Copyright (c) 2008 Paul Bakaus
  * Dual licensed under the MIT (MIT-LICENSE.txt)
  * and GPL (GPL-LICENSE.txt) licenses.
- * 
+ *
  * http://docs.jquery.com/UI/Sortables
  *
  * Depends:
@@ -12,37 +12,37 @@
  */
 (function($) {
 
-function contains(a, b) { 
-    var safari2 = $.browser.safari && $.browser.version < 522; 
-    if (a.contains && !safari2) { 
-        return a.contains(b); 
-    } 
+function contains(a, b) {
+    var safari2 = $.browser.safari && $.browser.version < 522;
+    if (a.contains && !safari2) {
+        return a.contains(b);
+    }
     if (a.compareDocumentPosition)
-        return !!(a.compareDocumentPosition(b) & 16); 
+        return !!(a.compareDocumentPosition(b) & 16);
     while (b = b.parentNode)
-          if (b == a) return true; 
-    return false; 
+          if (b == a) return true;
+    return false;
 };
 
 $.widget("ui.sortable", $.extend({}, $.ui.mouse, {
 	_init: function() {
-		
+
 		var o = this.options;
 		this.containerCache = {};
 		this.element.addClass("ui-sortable");
-		
+
 		//Get the items
 		this.refresh();
-		
+
 		//Let's determine if the items are floating
 		this.floating = this.items.length ? (/left|right/).test(this.items[0].item.css('float')) : false;
-		
+
 		//Let's determine the parent's offset
 		this.offset = this.element.offset();
-		
+
 		//Initialize mouse events for interaction
 		this._mouseInit();
-		
+
 	},
 	plugins: {},
 	ui: function(inst) {
@@ -55,114 +55,116 @@ $.widget("ui.sortable", $.extend({}, $.ui.mouse, {
 			element: this.element,
 			item: (inst || this)["currentItem"],
 			sender: inst ? inst.element : null
-		};		
+		};
 	},
-	
+
 	_propagate: function(n,e,inst, noPropagation) {
 		$.ui.plugin.call(this, n, [e, this.ui(inst)]);
 		if(!noPropagation) this.element.triggerHandler(n == "sort" ? n : "sort"+n, [e, this.ui(inst)], this.options[n]);
 	},
-	
+
 	serialize: function(o) {
-		
+
 		var items = this._getItemsAsjQuery(o && o.connected);
 		var str = []; o = o || {};
-		
+
 		$(items).each(function() {
 			var res = ($(o.item || this).attr(o.attribute || 'id') || '').match(o.expression || (/(.+)[-=_](.+)/));
 			if(res) str.push((o.key || res[1]+'[]')+'='+(o.key && o.expression ? res[1] : res[2]));
 		});
-		
+
 		return str.join('&');
-		
+
 	},
-	
+
 	toArray: function(o) {
-		
+
 		var items = this._getItemsAsjQuery(o && o.connected);
 		var ret = []; o = o || {};
-		
+
 		items.each(function() { ret.push($(o.item || this).attr(o.attribute || 'id') || ''); });
 		return ret;
-		
+
 	},
-	
+
 	/* Be careful with the following core functions */
 	_intersectsWith: function(item) {
 		var x1 = this.positionAbs.left, x2 = x1 + this.helperProportions.width,
 		y1 = this.positionAbs.top, y2 = y1 + this.helperProportions.height;
-		var l = item.left, r = l + item.width, 
+		var l = item.left, r = l + item.width,
 		t = item.top, b = t + item.height;
-		
+
 		var dyClick = this.offset.click.top, dxClick = this.offset.click.left;
 		var isOverElement = (y1 + dyClick) > t && (y1 + dyClick) < b && (x1 + dxClick) > l && (x1 + dxClick) < r;
-		
+
 		if(this.options.tolerance == "pointer" || this.options.forcePointerForContainers || (this.options.tolerance == "guess" && this.helperProportions[this.floating ? 'width' : 'height'] > item[this.floating ? 'width' : 'height'])) {
 			return isOverElement;
 		} else {
-			
+
 			return (l < x1 + (this.helperProportions.width / 2) // Right Half
 				&& x2 - (this.helperProportions.width / 2) < r // Left Half
 				&& t < y1 + (this.helperProportions.height / 2) // Bottom Half
 				&& y2 - (this.helperProportions.height / 2) < b ); // Top Half
-		
+
 		}
 	},
-	
-	_intersectsWithEdge: function(item) {	
-		var x1 = this.positionAbs.left, x2 = x1 + this.helperProportions.width,
-			y1 = this.positionAbs.top, y2 = y1 + this.helperProportions.height;
-		
-		var l = item.left, r = l + item.width, 
-			t = item.top, b = t + item.height;
-		
+
+	_intersectsWithEdge: function(item) {
 		var dyClick = this.offset.click.top, dxClick = this.offset.click.left;
-		var isOverElement = (y1 + dyClick) > t && (y1 + dyClick) < b && (x1 + dxClick) > l && (x1 + dxClick) < r;
-		
-		if(this.options.tolerance == "pointer" || (this.options.tolerance == "guess" && this.helperProportions[this.floating ? 'width' : 'height'] > item[this.floating ? 'width' : 'height'])) {
-			if(!isOverElement) return false;
-			
-			if(this.floating) {
-				if ((x1 + dxClick) > l && (x1 + dxClick) < l + item.width/2) return 2;
-				if ((x1 + dxClick) > l + item.width/2 && (x1 + dxClick) < r) return 1;
-			} else {
-				var height = item.height;
-				var direction = y1 - this.updateOriginalPosition.top < 0 ? 2 : 1; // 2 = up
-				
-				if (direction == 1 && (y1 + dyClick) < t + height/2) { return 2; } // up
-				else if (direction == 2 && (y1 + dyClick) > t + height/2) { return 1; } // down
+		var helperHeight = this.helperProportions.height, helperWidth = this.helperProportions.width;
+		var helperTop = this.positionAbs.top, helperLeft = this.positionAbs.left;
+		var itemHeight = item.height, itemWidth = item.width;
+		var itemTop = item.top, itemLeft = item.left;
+
+		var isOverElementHeight = ((helperTop + dyClick) > itemTop) &&
+								((helperTop + dyClick) < (itemTop + itemHeight));
+
+		var isOverElementWidth = ((helperLeft + dxClick) > itemLeft) &&
+								((helperLeft + dxClick) < (itemLeft + itemWidth));
+
+		var isOverElement = isOverElementHeight && isOverElementWidth;
+		var verticalDirection = this._getDragVerticalDirection();
+		var horizontalDirection = this._getDragHorizontalDirection();
+
+		if (this.floating) {
+			if (isOverElementWidth) {
+				return horizontalDirection == "right" ? 2 : 1;
 			}
-			
-		} else {
-			if (!(l < x1 + (this.helperProportions.width / 2) // Right Half
-				&& x2 - (this.helperProportions.width / 2) < r // Left Half
-				&& t < y1 + (this.helperProportions.height / 2) // Bottom Half
-				&& y2 - (this.helperProportions.height / 2) < b )) return false; // Top Half
-			
-			if(this.floating) {
-				if(x2 > l && x1 < l) return 2; //Crosses left edge
-				if(x1 < r && x2 > r) return 1; //Crosses right edge
-			} else {
-				if(y2 > t && y1 < t) return 1; //Crosses top edge
-				if(y1 < b && y2 > b) return 2; //Crosses bottom edge
+		}
+		else {
+			if (isOverElement) {
+				return verticalDirection == "down" ? 2 : 1;
 			}
 		}
-		
+
 		return false;
-		
 	},
-	
+
+	_getDragVerticalDirection: function() {
+		var helperTop = this.positionAbs.top;
+		var lastTop = this.lastPositionAbs.top;
+		var direction = helperTop - lastTop > 0 ? "down" : "up";
+		return direction;
+	},
+
+	_getDragHorizontalDirection: function() {
+		var helperLeft = this.positionAbs.left;
+		var lastLeft = this.lastPositionAbs.left;
+		var direction = helperLeft - lastLeft > 0 ? "right" : "left";
+		return direction;
+	},
+
 	refresh: function() {
 		this._refreshItems();
 		this.refreshPositions();
 	},
-	
+
 	_getItemsAsjQuery: function(connected) {
-		
+
 		var self = this;
 		var items = [];
 		var queries = [];
-		
+
 		if(this.options.connectWith && connected) {
 			for (var i = this.options.connectWith.length - 1; i >= 0; i--){
 				var cur = $(this.options.connectWith[i]);
@@ -174,42 +176,42 @@ $.widget("ui.sortable", $.extend({}, $.ui.mouse, {
 				};
 			};
 		}
-		
+
 		queries.push([$.isFunction(this.options.items) ? this.options.items.call(this.element, null, { options: this.options, item: this.currentItem }) : $(this.options.items, this.element).not(".ui-sortable-helper"), this]);
-		
+
 		for (var i = queries.length - 1; i >= 0; i--){
 			queries[i][0].each(function() {
 				items.push(this);
 			});
 		};
-		
+
 		return $(items);
-		
+
 	},
-	
+
 	_removeCurrentsFromItems: function() {
-		
-		var list = this.currentItem.find(":data(sortable-item)");	
-		
+
+		var list = this.currentItem.find(":data(sortable-item)");
+
 		for (var i=0; i < this.items.length; i++) {
-			
+
 			for (var j=0; j < list.length; j++) {
 				if(list[j] == this.items[i].item[0])
 					this.items.splice(i,1);
 			};
-			
+
 		};
-		
+
 	},
-	
+
 	_refreshItems: function() {
-		
+
 		this.items = [];
 		this.containers = [this];
 		var items = this.items;
 		var self = this;
 		var queries = [[$.isFunction(this.options.items) ? this.options.items.call(this.element, null, { options: this.options, item: this.currentItem }) : $(this.options.items, this.element), this]];
-		
+
 		if(this.options.connectWith) {
 			for (var i = this.options.connectWith.length - 1; i >= 0; i--){
 				var cur = $(this.options.connectWith[i]);
@@ -222,48 +224,54 @@ $.widget("ui.sortable", $.extend({}, $.ui.mouse, {
 				};
 			};
 		}
-		
-		for (var i = queries.length - 1; i >= 0; i--){
-			queries[i][0].each(function() {
-				$.data(this, 'sortable-item', queries[i][1]); // Data for target checking (mouse manager)
+
+		for (var i = queries.length - 1; i >= 0; i--) {
+			var targetData = queries[i][1];
+			var _queries = queries[i][0];
+
+			for (var j=0, queriesLength = _queries.length; j < queriesLength; j++) {
+				var item = $(_queries[j]);
+
+				item.data('sortable-item', targetData); // Data for target checking (mouse manager)
+
 				items.push({
-					item: $(this),
-					instance: queries[i][1],
+					item: item,
+					instance: targetData,
 					width: 0, height: 0,
 					left: 0, top: 0
 				});
-			});
+			};
 		};
-		
+
 	},
-	
+
 	refreshPositions: function(fast) {
-		
+
 		//This has to be redone because due to the item being moved out/into the offsetParent, the offsetParent's position will change
 		if(this.offsetParent) {
 			var po = this.offsetParent.offset();
 			this.offset.parent = { top: po.top + this.offsetParentBorders.top, left: po.left + this.offsetParentBorders.left };
 		}
-		
-		for (var i = this.items.length - 1; i >= 0; i--){		
-			
+
+		for (var i = this.items.length - 1; i >= 0; i--){
+			var item = this.items[i];
+
 			//We ignore calculating positions of all connected containers when we're not over them
-			if(this.items[i].instance != this.currentContainer && this.currentContainer && this.items[i].item[0] != this.currentItem[0])
+			if(item.instance != this.currentContainer && this.currentContainer && item.item[0] != this.currentItem[0])
 				continue;
-			
-			var t = this.options.toleranceElement ? $(this.options.toleranceElement, this.items[i].item) : this.items[i].item;
-			
-			if(!fast) {
-				this.items[i].width = t[0].offsetWidth;
-				this.items[i].height = t[0].offsetHeight;
+
+			var t = this.options.toleranceElement ? $(this.options.toleranceElement, item.item) : item.item;
+
+			if (!fast) {
+				item.width = t[0].offsetWidth;
+				item.height = t[0].offsetHeight;
 			}
-			
+
 			var p = t.offset();
-			this.items[i].left = p.left;
-			this.items[i].top = p.top;
-			
+			item.left = p.left;
+			item.top = p.top;
 		};
-		
+
 		if(this.options.custom && this.options.custom.refreshContainers) {
 			this.options.custom.refreshContainers.call(this);
 		} else {
@@ -275,40 +283,40 @@ $.widget("ui.sortable", $.extend({}, $.ui.mouse, {
 				this.containers[i].containerCache.height = this.containers[i].element.outerHeight();
 			};
 		}
-		
+
 	},
-	
+
 	destroy: function() {
 		this.element
 			.removeClass("ui-sortable ui-sortable-disabled")
 			.removeData("sortable")
 			.unbind(".sortable");
 		this._mouseDestroy();
-		
+
 		for ( var i = this.items.length - 1; i >= 0; i-- )
 			this.items[i].item.removeData("sortable-item");
 	},
-	
+
 	_createPlaceholder: function(that) {
-		
+
 		var self = that || this, o = self.options;
-		
+
 		if(!o.placeholder || o.placeholder.constructor == String) {
 			var className = o.placeholder;
 			o.placeholder = {
 				element: function() {
-					
+
 					var el = $(document.createElement(self.currentItem[0].nodeName))
 						.addClass(className || self.currentItem[0].className+" ui-sortable-placeholder")
 						.removeClass('ui-sortable-helper')[0];
-					
+
 					if(!className) {
 						el.style.visibility = "hidden";
 						document.body.appendChild(el);
 						el.innerHTML = self.currentItem[0].innerHTML;
 						document.body.removeChild(el);
 					};
-					
+
 					return el;
 				},
 				update: function(container, p) {
@@ -318,26 +326,26 @@ $.widget("ui.sortable", $.extend({}, $.ui.mouse, {
 				}
 			};
 		}
-		
+
 		//Create the placeholder
 		self.placeholder = $(o.placeholder.element.call(self.element, self.currentItem));
-		
+
 		//Append it after the actual current item
 		self.currentItem.after(self.placeholder);
-		
+
 		//Update the size of the placeholder (TODO: Logic to fuzzy, see line 316/317)
 		o.placeholder.update(self, self.placeholder);
-		
+
 	},
-	
+
 	_contactContainers: function(e) {
 		for (var i = this.containers.length - 1; i >= 0; i--){
-			
+
 			if(this._intersectsWith(this.containers[i].containerCache)) {
 				if(!this.containers[i].containerCache.over) {
-					
+
 					if(this.currentContainer != this.containers[i]) {
-						
+
 						//When entering a new container, we will find the item with the least distance and append our item near it
 						var dist = 10000; var itemWithLeastDistance = null; var base = this.positionAbs[this.containers[i].floating ? 'left' : 'top'];
 						for (var j = this.items.length - 1; j >= 0; j--) {
@@ -347,20 +355,20 @@ $.widget("ui.sortable", $.extend({}, $.ui.mouse, {
 								dist = Math.abs(cur - base); itemWithLeastDistance = this.items[j];
 							}
 						}
-						
+
 						if(!itemWithLeastDistance && !this.options.dropOnEmpty) //Check if dropOnEmpty is enabled
 							continue;
-						
+
 						this.currentContainer = this.containers[i];
 						itemWithLeastDistance ? this.options.sortIndicator.call(this, e, itemWithLeastDistance, null, true) : this.options.sortIndicator.call(this, e, null, this.containers[i].element, true);
 						this._propagate("change", e); //Call plugins and callbacks
 						this.containers[i]._propagate("change", e, this); //Call plugins and callbacks
-						
+
 						//Update the placeholder
 						this.options.placeholder.update(this.currentContainer, this.placeholder);
-						
+
 					}
-					
+
 					this.containers[i]._propagate("over", e, this);
 					this.containers[i].containerCache.over = 1;
 				}
@@ -370,136 +378,136 @@ $.widget("ui.sortable", $.extend({}, $.ui.mouse, {
 					this.containers[i].containerCache.over = 0;
 				}
 			}
-			
-		};			
+
+		};
 	},
-	
+
 	_mouseCapture: function(e, overrideHandle) {
-		
+
 		if(this.options.disabled || this.options.type == 'static') return false;
-		
+
 		//We have to refresh the items data once first
 		this._refreshItems();
-		
+
 		//Find out if the clicked node (or one of its parents) is a actual item in this.items
-		var currentItem = null, self = this, nodes = $(e.target).parents().each(function() {	
+		var currentItem = null, self = this, nodes = $(e.target).parents().each(function() {
 			if($.data(this, 'sortable-item') == self) {
 				currentItem = $(this);
 				return false;
 			}
 		});
 		if($.data(e.target, 'sortable-item') == self) currentItem = $(e.target);
-		
+
 		if(!currentItem) return false;
 		if(this.options.handle && !overrideHandle) {
 			var validHandle = false;
-			
+
 			$(this.options.handle, currentItem).find("*").andSelf().each(function() { if(this == e.target) validHandle = true; });
 			if(!validHandle) return false;
 		}
-		
+
 		this.currentItem = currentItem;
 		this._removeCurrentsFromItems();
-		return true;	
-		
+		return true;
+
 	},
-	
+
 	createHelper: function(e) {
-		
+
 		var o = this.options;
 		var helper = typeof o.helper == 'function' ? $(o.helper.apply(this.element[0], [e, this.currentItem])) : (o.helper == "original" ? this.currentItem :  this.currentItem.clone());
-		
+
 		if (!helper.parents('body').length)
 			$(o.appendTo != 'parent' ? o.appendTo : this.currentItem[0].parentNode)[0].appendChild(helper[0]); //Add the helper to the DOM if that didn't happen already
-		
+
 		return helper;
-		
+
 	},
-	
+
 	_mouseStart: function(e, overrideHandle, noActivation) {
-		
+
 		var o = this.options;
 		this.currentContainer = this;
-		
+
 		//We only need to call refreshPositions, because the refreshItems call has been moved to mouseCapture
 		this.refreshPositions();
-		
-		//Create and append the visible helper	
-		this.helper = this.createHelper(e);		
-		
+
+		//Create and append the visible helper
+		this.helper = this.createHelper(e);
+
 		/*
 		 * - Position generation -
 		 * This block generates everything position related - it's the core of draggables.
 		 */
-		
+
 		this.margins = {																				//Cache the margins
 			left: (parseInt(this.currentItem.css("marginLeft"),10) || 0),
 			top: (parseInt(this.currentItem.css("marginTop"),10) || 0)
-		};		
-		
+		};
+
 		this.offset = this.currentItem.offset();														//The element's absolute position on the page
 		this.offset = {																					//Substract the margins from the element's absolute offset
 			top: this.offset.top - this.margins.top,
 			left: this.offset.left - this.margins.left
 		};
-		
+
 		this.offset.click = {																			//Where the click happened, relative to the element
 			left: e.pageX - this.offset.left,
 			top: e.pageY - this.offset.top
 		};
-		
+
 		this.offsetParent = this.helper.offsetParent();													//Get the offsetParent and cache its position
-		var po = this.offsetParent.offset();			
-	
+		var po = this.offsetParent.offset();
+
 		this.offsetParentBorders = {
 			top: (parseInt(this.offsetParent.css("borderTopWidth"),10) || 0),
 			left: (parseInt(this.offsetParent.css("borderLeftWidth"),10) || 0)
 		};
-		
+
 		this.offset.parent = {																			//Store its position plus border
 			top: po.top + this.offsetParentBorders.top,
 			left: po.left + this.offsetParentBorders.left
 		};
-		
+
 		this.updateOriginalPosition = this.originalPosition = this._generatePosition(e);				//Generate the original position
 		this.domPosition = { prev: this.currentItem.prev()[0], parent: this.currentItem.parent()[0] };  //Cache the former DOM position
-		
+
 		//If o.placeholder is used, create a new element at the given position with the class
 		this.helperProportions = { width: this.helper.outerWidth(), height: this.helper.outerHeight() };//Cache the helper size
-		
+
 		if(o.helper == "original") {
 			this._storedCSS = { position: this.currentItem.css("position"), top: this.currentItem.css("top"), left: this.currentItem.css("left"), clear: this.currentItem.css("clear") };
 		} else {
 			this.currentItem.hide(); //Hide the original, won't cause anything bad this way
 		}
-		
+
 		//Position it absolutely and add a helper class
 		this.helper
 			.css({ position: 'absolute', clear: 'both' })
 			.addClass('ui-sortable-helper');
-		
-		//Create the placeholder	
+
+		//Create the placeholder
 		this._createPlaceholder();
-		
+
 		//Call plugins and callbacks
 		this._propagate("start", e);
-		
+
 		//Recache the helper size
 		if(!this._preserveHelperProportions)
 			this.helperProportions = { width: this.helper.outerWidth(), height: this.helper.outerHeight() };
-		
+
 		if(o.cursorAt) {
 			if(o.cursorAt.left != undefined) this.offset.click.left = o.cursorAt.left;
 			if(o.cursorAt.right != undefined) this.offset.click.left = this.helperProportions.width - o.cursorAt.right;
 			if(o.cursorAt.top != undefined) this.offset.click.top = o.cursorAt.top;
 			if(o.cursorAt.bottom != undefined) this.offset.click.top = this.helperProportions.height - o.cursorAt.bottom;
 		}
-		
+
 		/*
 		 * - Position constraining -
 		 * Here we prepare position constraining like grid and containment.
-		 */	
-		
+		 */
+
 		if(o.containment) {
 			if(o.containment == 'parent') o.containment = this.helper[0].parentNode;
 			if(o.containment == 'document' || o.containment == 'window') this.containment = [
@@ -508,12 +516,12 @@ $.widget("ui.sortable", $.extend({}, $.ui.mouse, {
 				$(o.containment == 'document' ? document : window).width() - this.offset.parent.left - this.helperProportions.width - this.margins.left - (parseInt(this.element.css("marginRight"),10) || 0),
 				($(o.containment == 'document' ? document : window).height() || document.body.parentNode.scrollHeight) - this.offset.parent.top - this.helperProportions.height - this.margins.top - (parseInt(this.element.css("marginBottom"),10) || 0)
 			];
-			
+
 			if(!(/^(document|window|parent)$/).test(o.containment)) {
 				var ce = $(o.containment)[0];
 				var co = $(o.containment).offset();
 				var over = ($(ce).css("overflow") != 'hidden');
-				
+
 				this.containment = [
 					co.left + (parseInt($(ce).css("borderLeftWidth"),10) || 0) - this.offset.parent.left,
 					co.top + (parseInt($(ce).css("borderTopWidth"),10) || 0) - this.offset.parent.top,
@@ -522,26 +530,26 @@ $.widget("ui.sortable", $.extend({}, $.ui.mouse, {
 				];
 			}
 		}
-		
+
 		//Post 'activate' events to possible containers
 		if(!noActivation) {
 			 for (var i = this.containers.length - 1; i >= 0; i--) { this.containers[i]._propagate("activate", e, this); }
 		}
-		
+
 		//Prepare possible droppables
 		if($.ui.ddmanager)
 			$.ui.ddmanager.current = this;
-		
+
 		if ($.ui.ddmanager && !o.dropBehaviour)
 			$.ui.ddmanager.prepareOffsets(this, e);
-		
+
 		this.dragging = true;
-		
+
 		this._mouseDrag(e); //Execute the drag once - this causes the helper not to be visible before getting its correct position
 		return true;
-		
+
 	},
-	
+
 	_convertPositionTo: function(d, pos) {
 		if(!pos) pos = this.position;
 		var mod = d == "absolute" ? 1 : -1;
@@ -560,9 +568,9 @@ $.widget("ui.sortable", $.extend({}, $.ui.mouse, {
 			)
 		};
 	},
-	
+
 	_generatePosition: function(e) {
-		
+
 		var o = this.options;
 		var position = {
 			top: (
@@ -578,9 +586,9 @@ $.widget("ui.sortable", $.extend({}, $.ui.mouse, {
 				+ (this.offsetParent[0] == document.body ? 0 : this.offsetParent[0].scrollLeft)	// The offsetParent's scroll position, not if the element is fixed
 			)
 		};
-		
+
 		if(!this.originalPosition) return position;										//If we are not dragging yet, we won't check for options
-		
+
 		/*
 		 * - Position constraining -
 		 * Constrain the position to a mix of grid, containment.
@@ -591,71 +599,79 @@ $.widget("ui.sortable", $.extend({}, $.ui.mouse, {
 			if(position.left > this.containment[2]) position.left = this.containment[2];
 			if(position.top > this.containment[3]) position.top = this.containment[3];
 		}
-		
+
 		if(o.grid) {
 			var top = this.originalPosition.top + Math.round((position.top - this.originalPosition.top) / o.grid[1]) * o.grid[1];
 			position.top = this.containment ? (!(top < this.containment[1] || top > this.containment[3]) ? top : (!(top < this.containment[1]) ? top - o.grid[1] : top + o.grid[1])) : top;
-			
+
 			var left = this.originalPosition.left + Math.round((position.left - this.originalPosition.left) / o.grid[0]) * o.grid[0];
 			position.left = this.containment ? (!(left < this.containment[0] || left > this.containment[2]) ? left : (!(left < this.containment[0]) ? left - o.grid[0] : left + o.grid[0])) : left;
 		}
-		
+
 		return position;
 	},
-	
+
 	_mouseDrag: function(e) {
-		
+
 		//Compute the helpers position
 		this.position = this._generatePosition(e);
 		this.positionAbs = this._convertPositionTo("absolute");
-		
+
+		if (!this.lastPositionAbs) {
+			this.lastPositionAbs = this.positionAbs;
+		}
+
 		//Call the internal plugins
 		$.ui.plugin.call(this, "sort", [e, this.ui()]);
-		
+
 		//Regenerate the absolute position used for position checks
 		this.positionAbs = this._convertPositionTo("absolute");
-		
+
 		//Set the helper's position
 		this.helper[0].style.left = this.position.left+'px';
 		this.helper[0].style.top = this.position.top+'px';
-		
+
 		//Rearrange
 		for (var i = this.items.length - 1; i >= 0; i--) {
+
 			var intersection = this._intersectsWithEdge(this.items[i]);
+
 			if(!intersection) continue;
-			
+
 			if(this.items[i].item[0] != this.currentItem[0] //cannot intersect with itself
 				&&	this.placeholder[intersection == 1 ? "next" : "prev"]()[0] != this.items[i].item[0] //no useless actions that have been done before
 				&&	!contains(this.placeholder[0], this.items[i].item[0]) //no action if the item moved is the parent of the item checked
 				&& (this.options.type == 'semi-dynamic' ? !contains(this.element[0], this.items[i].item[0]) : true)
 			) {
-				
+
 				this.updateOriginalPosition = this._generatePosition(e);
-				
+
 				this.direction = intersection == 1 ? "down" : "up";
 				this.options.sortIndicator.call(this, e, this.items[i]);
 				this._propagate("change", e); //Call plugins and callbacks
 				break;
 			}
 		}
-		
+
 		//Post events to containers
 		this._contactContainers(e);
-		
+
 		//Interconnect with droppables
 		if($.ui.ddmanager) $.ui.ddmanager.drag(this, e);
-		
+
 		//Call callbacks
 		this.element.triggerHandler("sort", [e, this.ui()], this.options["sort"]);
-		
+
+		this.lastPositionAbs = this.positionAbs;
+
 		return false;
-		
+
 	},
-	
+
 	_rearrange: function(e, i, a, hardRefresh) {
-		
+
 		a ? a[0].appendChild(this.placeholder[0]) : i.item[0].parentNode.insertBefore(this.placeholder[0], (this.direction == 'down' ? i.item[0] : i.item[0].nextSibling));
-		
+
 		//Various things done here to improve the performance:
 		// 1. we create a setTimeout, that calls refreshPositions
 		// 2. on the instance, we have a counter variable, that get's higher after every append
@@ -663,23 +679,23 @@ $.widget("ui.sortable", $.extend({}, $.ui.mouse, {
 		// 4. this lets only the last addition to the timeout stack through
 		this.counter = this.counter ? ++this.counter : 1;
 		var self = this, counter = this.counter;
-		
+
 		window.setTimeout(function() {
 			if(counter == self.counter) self.refreshPositions(!hardRefresh); //Precompute after each DOM insertion, NOT on mousemove
 		},0);
-		
+
 	},
-	
+
 	_mouseStop: function(e, noPropagation) {
-		
+
 		//If we are using droppables, inform the manager about the drop
 		if ($.ui.ddmanager && !this.options.dropBehaviour)
 			$.ui.ddmanager.drop(this, e);
-		
+
 		if(this.options.revert) {
 			var self = this;
 			var cur = self.placeholder.offset();
-			
+
 			$(this.helper).animate({
 				left: cur.left - this.offset.parent.left - self.margins.left + (this.offsetParent[0] == document.body ? 0 : this.offsetParent[0].scrollLeft),
 				top: cur.top - this.offset.parent.top - self.margins.top + (this.offsetParent[0] == document.body ? 0 : this.offsetParent[0].scrollTop)
@@ -689,22 +705,22 @@ $.widget("ui.sortable", $.extend({}, $.ui.mouse, {
 		} else {
 			this._clear(e, noPropagation);
 		}
-		
+
 		return false;
-		
+
 	},
-	
+
 	_clear: function(e, noPropagation) {
-		
+
 		//We first have to update the dom position of the actual currentItem
 		if(!this._noFinalSort) this.placeholder.before(this.currentItem);
 		this._noFinalSort = null;
-		
+
 		if(this.options.helper == "original")
 			this.currentItem.css(this._storedCSS).removeClass("ui-sortable-helper");
 		else
 			this.currentItem.show();
-		
+
 		if(this.domPosition.prev != this.currentItem.prev().not(".ui-sortable-helper")[0] || this.domPosition.parent != this.currentItem.parent()[0]) this._propagate("update", e, null, noPropagation); //Trigger update callback if the DOM position has changed
 		if(!contains(this.element[0], this.currentItem[0])) { //Node was moved out of the current element
 			this._propagate("remove", e, null, noPropagation);
@@ -715,7 +731,7 @@ $.widget("ui.sortable", $.extend({}, $.ui.mouse, {
 				}
 			};
 		};
-		
+
 		//Post events to containers
 		for (var i = this.containers.length - 1; i >= 0; i--){
 			this.containers[i]._propagate("deactivate", e, this, noPropagation);
@@ -724,22 +740,22 @@ $.widget("ui.sortable", $.extend({}, $.ui.mouse, {
 				this.containers[i].containerCache.over = 0;
 			}
 		}
-		
+
 		this.dragging = false;
 		if(this.cancelHelperRemoval) {
 			this._propagate("beforeStop", e, null, noPropagation);
 			this._propagate("stop", e, null, noPropagation);
 			return false;
 		}
-		
+
 		this._propagate("beforeStop", e, null, noPropagation);
-		
+
 		this.placeholder.remove();
 		if(this.options.helper != "original") this.helper.remove(); this.helper = null;
 		this._propagate("stop", e, null, noPropagation);
-		
+
 		return true;
-		
+
 	}
 }));
 
@@ -806,7 +822,7 @@ $.ui.plugin.add("sortable", "scroll", {
 	start: function(e, ui) {
 		var o = ui.options;
 		var i = $(this).data("sortable");
-		
+
 		i.overflowY = function(el) {
 			do { if(/auto|scroll/.test(el.css('overflow')) || (/auto|scroll/).test(el.css('overflow-y'))) return el; el = el.parent(); } while (el[0].parentNode);
 			return $(document);
@@ -815,16 +831,16 @@ $.ui.plugin.add("sortable", "scroll", {
 			do { if(/auto|scroll/.test(el.css('overflow')) || (/auto|scroll/).test(el.css('overflow-x'))) return el; el = el.parent(); } while (el[0].parentNode);
 			return $(document);
 		}(i.currentItem);
-		
+
 		if(i.overflowY[0] != document && i.overflowY[0].tagName != 'HTML') i.overflowYOffset = i.overflowY.offset();
 		if(i.overflowX[0] != document && i.overflowX[0].tagName != 'HTML') i.overflowXOffset = i.overflowX.offset();
-		
+
 	},
 	sort: function(e, ui) {
-		
+
 		var o = ui.options;
 		var i = $(this).data("sortable");
-		
+
 		if(i.overflowY[0] != document && i.overflowY[0].tagName != 'HTML') {
 			if((i.overflowYOffset.top + i.overflowY[0].offsetHeight) - e.pageY < o.scrollSensitivity)
 				i.overflowY[0].scrollTop = i.overflowY[0].scrollTop + o.scrollSpeed;
@@ -836,7 +852,7 @@ $.ui.plugin.add("sortable", "scroll", {
 			if($(window).height() - (e.pageY - $(document).scrollTop()) < o.scrollSensitivity)
 				$(document).scrollTop($(document).scrollTop() + o.scrollSpeed);
 		}
-		
+
 		if(i.overflowX[0] != document && i.overflowX[0].tagName != 'HTML') {
 			if((i.overflowXOffset.left + i.overflowX[0].offsetWidth) - e.pageX < o.scrollSensitivity)
 				i.overflowX[0].scrollLeft = i.overflowX[0].scrollLeft + o.scrollSpeed;
@@ -848,18 +864,18 @@ $.ui.plugin.add("sortable", "scroll", {
 			if($(window).width() - (e.pageX - $(document).scrollLeft()) < o.scrollSensitivity)
 				$(document).scrollLeft($(document).scrollLeft() + o.scrollSpeed);
 		}
-		
+
 	}
 });
 
 $.ui.plugin.add("sortable", "axis", {
 	sort: function(e, ui) {
-		
+
 		var i = $(this).data("sortable");
-		
+
 		if(ui.options.axis == "y") i.position.left = i.originalPosition.left;
 		if(ui.options.axis == "x") i.position.top = i.originalPosition.top;
-		
+
 	}
 });