Calendar issue - changing month (next or prev) doesn't update calendar title

Hello,

Here is the problem :

When the calendar is loaded : everything is fine.
Calendar Title = current Month (April) : OK
Calendar content = current Month (April) : OK


When you click on next month
Calendar Title = current Month (April) instead of next Month (May) : Not OK
Calendar content = next Month (May) : OK


When you click again on next month
Calendar Title = May instead of next next Month (June) : Not OK
Calendar content = June : OK


Seems similar to this issue : http://stackideas.com/forums/mini-calendar-in-sidebar-not-advancing-month
But I tried attachment file and it didn't work so I get back to original file.

If you need extra informations, just ask

Regards