Autocomplete: Track pending requests and only remove the loading clas…

…s when the last request completes. Fixes #6761 - Autocomplete: Loading class removed when multiple Ajax requests occur.

ui/jquery.ui.autocomplete.js

@@ -26,6 +26,9 @@ $.widget( "ui.autocomplete", {
 		},
 		source: null
 	},
+
+	pending: 0,
+
 	_create: function() {
 		var self = this,
 			doc = this.element[ 0 ].ownerDocument,
@@ -289,6 +292,7 @@ $.widget( "ui.autocomplete", {
 	},
 
 	_search: function( value ) {
+		this.pending++;
 		this.element.addClass( "ui-autocomplete-loading" );
 
 		this.source( { term: value }, this.response );
@@ -302,7 +306,10 @@ $.widget( "ui.autocomplete", {
 		} else {
 			this.close();
 		}
-		this.element.removeClass( "ui-autocomplete-loading" );
+		this.pending--;
+		if ( !this.pending ) {
+			this.element.removeClass( "ui-autocomplete-loading" );
+		}
 	},
 
 	close: function( event ) {