We have noticed that Date Picker behaves differently in AJAX and IE Plugin. For example if in Month Jun 2011 the underlying Date table has only values starting from 1st Jun to 20th Jun and we have Caledar object based on Date column. Now if we see this calendar object in AJAX client then Date Values after 20th would be greyed out while IE plugin does not grayed out the dates. In IE Plugin if user select a date which is not present in Date column then it does not allow the selection and previously selected Date remains in date selection. It is bit confusing for users in one client Date picker disable the dates and another it does not.
Our customer wants to see the background color of disabled dates as different then Grey which can be customized for Ajax client by customizing the properties in theme.css present in \Server\QlikViewClients\QlikViewAjax\htc\Calendar\skins\aqua. Not sure if this is right apporach but it is working.
In case of IE Plugin can we do customization of Values shown in calendar by changing properties in some files.