one of my users has requested the ability to have the daytime picker pop-up closed when you double-click on the time.  could this please be added into a future release. I have written some code to do it in the meantime in ClockItem.cs:

// Stefan: start
        protected override void OnMouseDoubleClick(MouseButtonEventArgs e)
        {
            base.OnMouseDoubleClick(e);
            var dateTimePicker = this.ParentOfType<RadDateTimePicker>();
            if (dateTimePicker != null && dateTimePicker.InputBox != null)
            {
                dateTimePicker.IsDropDownOpen = false; // close it.
            }
        }
        // Stefan: end

When the control is declared in XAML, and we place the caret somewhere on the control the VS designer is open, and the dropdown is open.

Research and implement if possible to choose seconds TimeInterval.

This is the error: This feature requires service 'Microsoft.Windows.Design.Services.ValueTranslationService' to be present, but it could not be located.

Available in LIB version 2015.3.1026, it will be also available in the 2015 Q3 SP.

Can you please add a property CustomFormat to RadDateTimePicker?  Possibly we should have 3 options for DisplayMode: Short, Long and Custom.  If Custom is selected, user can specify format into CustomFormat field.  Ex. CustomFormat = "MMM dd, yyyy".  Also, make this field bindable, so that it can be specified from the ViewModel.

Available in LIB version 2016.3.1017, it will be also available in the 2016 R3 SP1 release. 

The milliseconds are not correctly parsed when setting an (f) custom format to the ShortTimePattern property.

A workaround for this would be to implement custom parsing:

private void TimePicker_ParseDateTimeValue(object sender, Telerik.Windows.Controls.ParseDateTimeEventArgs args)
{
    string input = args.TextToParse;

    DateTime res;
    bool isValueParsedSuccessfully = DateTime.TryParse(input, out res);

    if (isValueParsedSuccessfully)
    {
        args.Result = res;
    }
    else
    {
        args.IsParsingSuccessful = false;
    }
}

For example after entering "7 July 2014" hitting the enter keyboard key causes ArgumentOutOfRangeException

A client could change the TimeZoneInfo in the DateTimePicker control so it will shows the DateTime information different from the current machine.