diff --git a/ui/jquery.ui.autocomplete.js b/ui/jquery.ui.autocomplete.js
index 070045d16ab..1a38814569a 100644
--- a/ui/jquery.ui.autocomplete.js
+++ b/ui/jquery.ui.autocomplete.js
@@ -17,7 +17,8 @@
 $.widget( "ui.autocomplete", {
 	options: {
 		minLength: 1,
-		delay: 300
+		delay: 300,
+		separator: false
 	},
 	_create: function() {
 		var self = this,
@@ -108,14 +109,26 @@ $.widget( "ui.autocomplete", {
 					if ( false !== self._trigger( "focus", null, { item: item } ) ) {
 						// use value to match what will end up in the input, if it was a key event
 						if ( /^key/.test(event.originalEvent.type) ) {
-							self.element.val( item.value );
+							if(self.options.separator){
+								var val = self._insertValue(item.value);
+								self.element.val( val );
+								$.ui.autocomplete.caret( self.element, val.length - self.valEndLength );
+							} else {
+								self.element.val( item.value );
+							}
 						}
 					}
 				},
 				selected: function( event, ui ) {
 					var item = ui.item.data( "item.autocomplete" );
 					if ( false !== self._trigger( "select", event, { item: item } ) ) {
-						self.element.val( item.value );
+						if(self.options.separator){
+							var val = self._insertValue(item.value);
+							self.element.val( val );
+							$.ui.autocomplete.caret( self.element, val.length - self.valEndLength );
+						} else {
+							self.element.val( item.value );
+						}
 					}
 					self.close( event );
 					// only trigger when focus was lost (click on menu)
@@ -198,7 +211,51 @@ $.widget( "ui.autocomplete", {
 			// always save the actual value, not the one passed as an argument
 			.val();
 
-		this.source( { term: value }, this.response );
+		if( this.options.separator ){
+			var caretPos = $.ui.autocomplete.caret(this.element).end;
+			value = this._getValue( value, caretPos );
+			this._storeTermBits( caretPos );
+		}
+		if( value ){
+			this.source( { term: value }, this.response );
+		}
+	},
+	
+	_getValue: function( value, caretPos ){
+		/*
+		 * Cut the string in half at the caret, split at the separators,
+		 * and then concat the outter array values so that editing the
+		 * middle of a string still correctly triggers the autocomplete
+		 */
+		var begin = value.substr( 0, caretPos ).split( this.options.separator ),
+			end = value.substr( caretPos );
+		this.valEndLength = end.length;
+		
+		return begin[ begin.length-1 ] + end.split( this.options.separator )[0];
+	},
+	
+	_storeTermBits: function( caretPos ){
+		/*
+		 * Store the beginning and end of the original term so that
+		 * the values can quickly be swapped in and out in _insertValue
+		 */	
+		this.termBegin = this.term.substr( 0, caretPos ).split( this.options.separator );
+		this.termEnd = this.term.substr( caretPos ).split( this.options.separator );
+		//clean the arrays of empty entries
+		this.termBegin.pop();
+		this.termEnd.shift();
+	},
+	
+	_insertValue: function( value ){
+		var result = '';
+		if( this.termBegin.length ){
+			result = this.termBegin.join( this.options.separator ) + this.options.separator;
+		}
+		result += value;
+		if( this.termEnd.length ){
+			result += this.options.separator + this.termEnd.join( this.options.separator );
+		}
+		return result;
 	},
 
 	_response: function( content ) {
@@ -310,6 +367,34 @@ $.extend( $.ui.autocomplete, {
 		return $.grep( array, function(value) {
 			return matcher.test( value.label || value.value || value );
 		});
+	},
+	caret: function(element, begin, end) {	//Helper Function for Caret positioning taken from http://dev.jqueryui.com/browser/branches/dev/mask/ui/ui.mask.js?rev=2371
+		var input = element[0];
+		if (typeof begin == 'number') {
+			end = (typeof end == 'number') ? end : begin;
+			if (input.setSelectionRange) {
+				input.focus();
+				input.setSelectionRange(begin, end);
+			} else if (input.createTextRange) {
+				var range = input.createTextRange();
+				range.collapse(true);
+				range.moveEnd('character', end);
+				range.moveStart('character', begin);
+				range.select();
+			}
+			return element;
+		} else {
+			if (input.setSelectionRange) {
+				begin = input.selectionStart;
+				end = input.selectionEnd;
+			}
+			else if (document.selection && document.selection.createRange) {
+				var range = document.selection.createRange();
+				begin = 0 - range.duplicate().moveStart('character', -100000);
+				end = begin + range.text.length;
+			}
+			return { begin: begin, end: end };
+		}
 	}
 });