Ticket #4417: ui.selectable.js.patch

--- ui.selectable.js	2009-04-10 17:18:09.000000000 -0500
+++ ui.selectable.js.multiselect	2009-04-10 17:31:52.000000000 -0500
@@ -48,9 +48,9 @@ $.widget("ui.selectable", $.extend({}, $
 
 		this._mouseInit();
 
-		this.helper = $(document.createElement('div'))
-			.css({border:'1px dotted black'})
-			.addClass("ui-selectable-helper");
+		this.helper = $(document.createElement('div')).addClass("ui-selectable-helper");
+		if (this.options.multiselect)
+			this.helper.css({border:'1px dotted black'});
 	},
 
 	destroy: function() {
@@ -93,7 +93,7 @@ $.widget("ui.selectable", $.extend({}, $
 		this.selectees.filter('.ui-selected').each(function() {
 			var selectee = $.data(this, "selectable-item");
 			selectee.startselected = true;
-			if (!event.metaKey) {
+			if (!event.metaKey || !options.multiselect) {
 				selectee.$element.removeClass('ui-selected');
 				selectee.selected = false;
 				selectee.$element.addClass('ui-unselecting');
@@ -126,7 +126,7 @@ $.widget("ui.selectable", $.extend({}, $
 		var self = this;
 		this.dragged = true;
 
-		if (this.options.disabled)
+		if (this.options.disabled || !this.options.multiselect)
 			return;
 
 		var options = this.options;
@@ -250,7 +250,8 @@ $.extend($.ui.selectable, {
 		delay: 0,
 		distance: 0,
 		filter: '*',
-		tolerance: 'touch'
+		tolerance: 'touch',
+		multiselect: true
 	}
 });