Product: Telerik UI for WPF

Control: RadDatePicker (custom inherited as NewDatePicker)

Target Framework: .NET Framework 4.7

Issue Summary:

W're facing an inconsistency in behavior with the RadDatePicker control between development and test environments.

• We have a custom control NewDatePicker that inherits from RadDatePicker.
• At runtime, we bind a SelectedDate value (e.g., Jan 23, 2025) to the control.
• When the user clicks to open the calendar popup:
  •   In development, the calendar popup correctly opens to SelectedDate.
  •   In test, the calendar popup opens to today's date (July 2025) instead of the bound SelectedDate.

Steps to Reproduce:

1. Use a RadDatePicker or inherited control.

        2. Set SelectedDate = DateTime.Now.AddMonths(-6) (e.g., Jan 23, 2025).

        3. Run the application and open the DatePicker calendar.

        4. Observe the calendar view:

•  Dev: shows January 2025 (as expected).
•  Test: jumps to current date (July 2025), even though SelectedDate is Jan 23.
  
  

What We Tried:

• Manually calling this.DisplayDate = this.SelectedDate.Value; inside OnPreviewMouseDown.
• Using Dispatcher.BeginInvoke(..., DispatcherPriority.Loaded) to defer the update.
• Accessing and setting PART_Calendar.DisplayDate explicitly.
• Ensured that SelectedDate has a valid value.
• Tried handling Loaded, OnApplyTemplate, and custom SyncDisplayDate() method.
• Everything works well in development — but not in the test environment.
  
  
  Questions:
  1. Is there a recommended approach to ensure the calendar opens to the correct month consistently in all environments?

Note: In Test environment First time click that time its show the current Date secound time I click that time it show the expected output. 

• the below the calendar need to show the 23 jan 2025 but its show current date.
  
  

I using the <telerik:RadDatePicker> 

 DisplayFormat = (Long or short) only there I need a customer format how we archive.

Example : 1 July 2025, 1 JUL 2025

Is it possible to have the RadCalendar inside the RadDatePicker and RadDateRangePicker to have a different theme than the RadDatePicker and the RadDateRangePicker?

I tried setting this within the RadDatePicker control's xaml:

<telerik:RadDateTimePicker.CalendarStyle>
    <Style TargetType="telerik:RadCalendar">
        <Setter Property="telerik:StyleManager.Theme"
                Value="Windows11" />
    </Style>
</telerik:RadDateTimePicker.CalendarStyle>

...but it has no effect.

Hello,

How can I change the header button text color and the week number text color (see attachment)?

Kind regards

Hello,

I want to know if its possible to update Gantt Tasks when you change a Start Date or End Date from the Grid View part. For example, if I delay Proptotype Task, all the task behind should be delayed the same time as Prototype.

Hi,

I used RadTimeSpanPicker, but I got a situation where I also needed a date.

So I want to use RadDateTimePicker as in the picture,

But with the RadTimeSpanPicker clock and not with the clock that RadDateTimePicker has.

I would be happy to help if this can be done and how

Thank you.

I want to change DateTime.Now format like MM/dd/yyyy throughout application. so please help me out.

Thanks & Regards

Murugan M