I have found the following which is very WIERD.
On Windows XP and Windows 7 Cal.setSensitive(startdt,enddt) is doing the following in both IE and FireFox:
After BST to DST change in March 2012 up to the end of April 2012 the ‘startdt’ is automatically adding an extra day to the date being given. e.g.
startdt = new Date(2012,3,16);
enddt = new Date(2012,11,31);
Cal.setSensitive(startdt,enddt);
This will ONLY allow dates from 17th April onwards to be selected in the Calendar. It only seems to happen for the above mentioned period i.e. after change from BST to DST to end of April. It is also happening for 2013 as well.
Note this works correctly in Linux on FireFox.
It looks like the problem is Windows OpSys related rather than browser related.
Please can you confirm / help.
Thanks
Purvez Desai