MonthYearPickerClientEvents

There can be some conditions you do want not to close the calendar popup on click over it. Then you should cancel the event either by return false; or set its argument args.CancelClose = true;

            <script type="text/javascript">
function Closing(sender, args)
{
    args.CancelClose = true;
    //or
    return false;
}
</script>
<radCln:RadDatePicker ID="RadDatePicker1" runat="server">
    <ClientEvents OnPopupClosing="Closing"/>
</radCln:RadDatePicker>
            

There can be some conditions you do want not to open the calendar popup on click of the popup button. Then you should cancel the event either by return false; or set its argument args.CancelOpen = true;

            <script type="text/javascript">
function Opening(sender, args)
{
    args.CancelOpen = true;
    //or
    return false;
}
</script>
<radCln:RadDatePicker ID="RadDatePicker1" runat="server">
    <ClientEvents OnPopupOpening="Opening"/>
</radCln:RadDatePicker>
                

Set the args.CancelSynchronize = true; to override the default DatePicker behavior of synchronizing the date in the DateInput and Calendar controls. This is useful for focusing the Calendar control on a date different from the DateInput one.

            <script type="text/javascript">
function Opening(sender, args)
{
    args.CancelCalendarSynchronize = true;
    sender.Calendar.NavigateToDate([2006,12,19]);
}
</script>
<radCln:RadDatePicker ID="RadDatePicker1" runat="server" >
    <ClientEvents OnPopupOpening="Opening"/>
</radCln:RadDatePicker>