Draggable: Ensure helper is positioned even if its the element itself

Fixes #9446

Author: mikesherov

tests/unit/draggable/draggable_options.js

@@ -701,6 +701,25 @@ test( "helper, default, switching after initialization", function() {
 	TestHelpers.draggable.shouldMove( element, "helper: original" );
 });
 
+// http://bugs.jqueryui.com/ticket/9446
+// Draggable: helper function cannot emulate default behavior
+test( "helper, function returning original element", function() {
+	expect( 1 );
+
+	var element = $( "#draggable1" ).css( "position", "static" ).draggable({
+		helper: function() {
+			return this;
+		}
+	});
+
+	TestHelpers.draggable.testDragHelperOffset( element, 100, 100, 100, 100, "original element is draggable" );
+
+	element.simulate( "drag", {
+		dx: 100,
+		dy: 100
+	});
+});
+
 function testHelperPosition( scrollPositions, position, helper, scrollElements, scrollElementsTitle ) {
 	test( "{ helper: '" + helper + "' }, " + position + ", with scroll offset on " + scrollElementsTitle, function() {
 		expect( scrollPositions.length * 2 );

ui/draggable.js

@@ -61,8 +61,8 @@ $.widget("ui.draggable", $.ui.mouse, {
 	},
 	_create: function() {
 
-		if (this.options.helper === "original" && !(/^(?:r|a|f)/).test(this.element.css("position"))) {
-			this.element[0].style.position = "relative";
+		if ( this.options.helper === "original" ) {
+			this._setPositionRelative();
 		}
 		if (this.options.addClasses){
 			this.element.addClass("ui-draggable");
@@ -345,12 +345,24 @@ $.widget("ui.draggable", $.ui.mouse, {
 	_createHelper: function(event) {
 
 		var o = this.options,
-			helper = $.isFunction(o.helper) ? $(o.helper.apply(this.element[ 0 ], [ event ])) : (o.helper === "clone" ? this.element.clone().removeAttr("id") : this.element);
+			helperIsFunction = $.isFunction( o.helper ),
+			helper = helperIsFunction ?
+				$( o.helper.apply( this.element[ 0 ], [ event ] ) ) :
+				( o.helper === "clone" ?
+					this.element.clone().removeAttr( "id" ) :
+					this.element );
 
 		if (!helper.parents("body").length) {
 			helper.appendTo((o.appendTo === "parent" ? this.element[0].parentNode : o.appendTo));
 		}
 
+		// http://bugs.jqueryui.com/ticket/9446
+		// a helper function can return the original element
+		// which wouldn't have been set to relative in _create
+		if ( helperIsFunction && helper[ 0 ] === this.element[ 0 ] ) {
+			this._setPositionRelative();
+		}
+
 		if (helper[0] !== this.element[0] && !(/(fixed|absolute)/).test(helper.css("position"))) {
 			helper.css("position", "absolute");
 		}
@@ -359,6 +371,12 @@ $.widget("ui.draggable", $.ui.mouse, {
 
 	},
 
+	_setPositionRelative: function() {
+		if ( !( /^(?:r|a|f)/ ).test( this.element.css( "position" ) ) ) {
+			this.element[ 0 ].style.position = "relative";
+		}
+	},
+
 	_adjustOffsetFromHelper: function(obj) {
 		if (typeof obj === "string") {
 			obj = obj.split(" ");