Hello Gavin,

There are different approaches to solve this task. Maybe the easiest solution could be if you are using UltraCalendarCombo control instead of UltraDateTimeEditor. If you are using UltraCalendarCombo you could apply your CurrentCulture settings.

Option 2: If you need to use UltraDateTimeEditor

It is possible but please note that there is no built-in support. The dropdown part of our UltraDateTimeEditor is Microsoft`s MonthCalendar which supporting localization from LocalUserDefault registry key. For more details you could take a look at:http://msdn.microsoft.com/en-us/library/windows/desktop/bb760913%28v=vs.85%29.aspx#localization  So, to be able to solve your task we could use the code below:

  private void ultraDateTimeEditor1_BeforeDropDown(object sender, CancelEventArgs e)
        {
            originalLang = Registry.GetValue(@"HKEY_CURRENT_USER\Control Panel\International", "LocaleName", "en-US").ToString();
            Registry.SetValue(@"HKEY_CURRENT_USER\Control Panel\International", "LocaleName", ultraComboEditor1.SelectedItem.DataValue);
        }

        private void ultraDateTimeEditor1_AfterCloseUp(object sender, EventArgs e)
        {
            Registry.SetValue(@"HKEY_CURRENT_USER\Control Panel\International", "LocaleName", originalLang);
        }

Please take a look at the attached sample and video file for more details. If you have any questions, feel free to write me

Regards