OS: MS Windows Vista
Browsers: IE9, FF4

I noticed several DST issues with DatePicker under MS Windows (Vista on my side)

To reproduce the issue:
1. Set time zone (GMT+2 Amman) in the Date and Time settings of Windows
2. Set 1 april ad current date
3. Open example (http://dev.sencha.com/deploy/ext-4.0.../xml-form.html)
4. Choose 30 April 2011 (04/30/2011) from picker in the date field
5. Edit date to 05/1/2011 (1 May) (IMPORTANT: change date manually in the field using keyboard, do not use picker)
6. Open picker and notice that selected date is 31 April in the picker, tooltip on that cell (31 april) shows 01 May
7. Notice that today button select 01 March instead 01 April
8. If execute the following code in the console
      Ext.Date.clearTime(new Date(2011, 3, 1))
then you get 31 March 2011