$.widget( "ui.combobox", {
	_create: function() {
		var self = this,
			select = this.element.hide(),
			selected = select.children( ":selected" ),
			value = selected.val() ? selected.text() : "";
		var input = this.input = $( "<input>" )
			.insertAfter( select )
			.val( value )
			.autocomplete({
				delay: 0,
				minLength: 0,
				source: function( request, response ) {
					var matcher = new RegExp( $.ui.autocomplete.escapeRegex(request.term), "i" );
					response( select.children( "option" ).map(function() {
						var text = $( this ).text();
						if ( this.value && ( !request.term || matcher.test(text) ) )
							return {
								label: text.replace(
									new RegExp(
										"(?![^&;]+;)(?!<[^<>]*)(" +
										$.ui.autocomplete.escapeRegex(request.term) +
										")(?![^<>]*>)(?![^&;]+;)", "gi"
									), "<strong>$1</strong>" ),
								value: text,
								option: this
							};
					}) );
				},
				select: function( event, ui ) {
					ui.item.option.selected = true;
					self._trigger( "selected", event, {
						item: ui.item.option
					});
				},
				change: function( event, ui ) {
					if ( !ui.item ) {
						var matcher = new RegExp( "^" + $.ui.autocomplete.escapeRegex( $(this).val() ) + "$", "i" ),
							valid = false;
						select.children( "option" ).each(function() {
							if ( $( this ).text().match( matcher ) ) {
								this.selected = valid = true;
								return false;
							}
						});
						if ( !valid ) {
							// remove invalid value, as it didn't match anything
							$( this ).val( "" );
							select.val( "" );
							input.data( "autocomplete" ).term = "";
							return false;
						}
					}
				}
			})
			.addClass( "ui-widget ui-widget-content ui-corner-left" );

		input.data( "autocomplete" )._renderItem = function( ul, item ) {
			return $( "<li></li>" )
				.data( "item.autocomplete", item )
				.append( "<a>" + item.label + "</a>" )
				.appendTo( ul );
		};

		this.button = $( "<button type='button'>&nbsp;</button>" )
			.attr( "tabIndex", -1 )
			.attr( "title", "Show All Items" )
			.insertAfter( input )
			.button({
				icons: {
					primary: "ui-icon-triangle-1-s"
				},
				text: false
			})
			.removeClass( "ui-corner-all" )
			.addClass( "ui-corner-right ui-button-icon" )
			.click(function() {
				// close if already visible
				if ( input.autocomplete( "widget" ).is( ":visible" ) ) {
					input.autocomplete( "close" );
					return;
				}

				// pass empty string as value to search for, displaying all results
				input.autocomplete( "search", "" );
				input.focus();
			});
	},

	destroy: function() {
		this.input.remove();
		this.button.remove();
		this.element.show();
		$.Widget.prototype.destroy.call( this );
	}
});