RadDateTimePicker Index was out range

[Brian]

I am working on the Bug Tracker sample and am getting this error when I try to run the program;

System.ArgumentOutOfRangeException: 'Index was out of range.

Must be a non-negative and less than size of the collection.

Parameter name index'

Below is the offending code. I am not seeing what is wrong with this;

private void ReadOnlyControls(bool readOnly)
{
    titleTextBox.ReadOnly = readOnly;
    idSpinEditor.ReadOnly = readOnly;
    descriptionTextBox.ReadOnly = readOnly;
    stepsToReproduceTextBox.ReadOnly = readOnly;
    idSpinEditor.ShowUpDownButtons = !readOnly;

    dateDateTimePicker.DateTimePickerElement.TextBoxElement.TextBoxItem.ReadOnly = readOnly;
    RadDateTimePickerArrowButtonElement arrowButton = dateDateTimePicker.DateTimePickerElement.Children[1].Children[1] as RadDateTimePickerArrowButtonElement;
    arrowButton.Visibility = readOnly ? ElementVisibility.Collapsed : ElementVisibility.Visible;

    priorityDropDownList.DropDownListElement.ArrowButton.Visibility = readOnly ? ElementVisibility.Collapsed : ElementVisibility.Visible;
    priorityDropDownList.DropDownListElement.TextBox.TextBoxItem.ReadOnly = readOnly;

    statusDropDownList.DropDownListElement.ArrowButton.Visibility = readOnly ? ElementVisibility.Collapsed : ElementVisibility.Visible;
    statusDropDownList.DropDownListElement.TextBox.TextBoxItem.ReadOnly = readOnly;

    ownerDropDownList.DropDownListElement.ArrowButton.Visibility = readOnly ? ElementVisibility.Collapsed : ElementVisibility.Visible;
    ownerDropDownList.DropDownListElement.TextBox.TextBoxItem.ReadOnly = readOnly;
}

[Dess | Tech Support Engineer, Principal]

Hello, Brian,   
 
According to the provided information, I suppose that you are referring to the BugTracker sample project which is located in the installation folder of our suite which is usually located at the following path: C:\Program Files (x86)\Progress\Telerik UI for WinForms R1 2018\Examples\BugTracker

When I try to run the project it seems to behave as expected on my end with the latest version. Please refer to the attached gif file illustrating the behavior I observe. Am I missing something? Do I have to perform any changes in the project before running it? Could you please specify the exact steps how to reproduce the problem? Thank you in advance for your cooperation.

I am looking forward to your reply. 

 Regards,
Dess
Progress Telerik

[Brian]

Thanks Dess, I was using the version of the application from online, not from the samples in the build. The sample from the build runs fine. Please disregard.