Date Picker Dialog: fixes bug when clicking on a disabled day (pull #…

…1095)

In the calendar grid in the date picker dialog, days that are in a previous or next month can appear in the grid.
These are disabled. Clicking them generated a JS error.
This fix causes the month displayed in the grid to change to the month that includes the day clicked.

examples/dialog-modal/js/datepicker-day.js

@@ -161,7 +161,7 @@ DatePickerDay.prototype.handleKeyDown = function (event) {
 DatePickerDay.prototype.handleMouseDown = function (event) {
 
   if (this.isDisabled()) {
-    this.datepicker.moveFocusToDay(this.date);
+    this.datepicker.moveFocusToDay(this.day);
   }
   else {
     this.datepicker.setTextboxDate(this.day);