Datepicker: Fix this reference in _hideDatepicker(). Fixed #7722 - Datepicker: Does not properly clear current instance when hidden.

Author: Jay Oster

ui/jquery.ui.datepicker.js

@@ -807,9 +807,10 @@ $.extend(Datepicker.prototype, {
 		if (this._datepickerShowing) {
 			var showAnim = this._get(inst, 'showAnim');
 			var duration = this._get(inst, 'duration');
+			var self = this;
 			var postProcess = function() {
 				$.datepicker._tidyDialog(inst);
-				this._curInst = null;
+				self._curInst = null;
 			};
 
 			// DEPRECATED: after BC for 1.8.x $.effects[ showAnim ] is not needed