https://msdn.microsoft.com/en-us/library/system.windows.forms.maskedtextbox.maskcompleted(v=vs.110).aspx

To reproduce:
this.radDateTimePicker1.DateTimePickerElement.TextBoxElement.MaskType = MaskType.FreeFormDateTime;

And try pasting a date, or some free text.

 

The new functionality should prevent duplicates to be added as tokens in the editor. An already selected item should not be visible in the popup as well. 

The attached 1148813-AutocompleteDuplicates.zip project features a possible custom solution. 

Workaround: use simple data binding with the editor and its Text property

this.radCalculatorDropDown1.CalculatorElement.EditorContentElement.TextBoxItem.DataBindings.Add("Text", testObject, "TestValue", false, DataSourceUpdateMode.OnPropertyChanged);

One should be able to disable the saving of the custom colors. In addition one should be able to override the color dialog FormClosing method.

When the IP is set like this:
this.radMaskedEditBox1.Value = "89.111.222.123";
the value in the box is not correct:
891.112.221.23

In addition the user should be able to insert digits not just replace them. 

When you have a GridViewDateTimeColumn in the RadGridView and enter in edit mode, you are allowed to clear the current date (set it to null) pressing the Clear button in the popup calendar. However, this functionality is not available in the RadDateTimePicker control.

Workaround:

 public Form1()
 {
     InitializeComponent();
     this.radDateTimePicker1.NullText = "Empty";

     RadDateTimePickerCalendar calendarBehavior = this.radDateTimePicker1.DateTimePickerElement.GetCurrentBehavior() as RadDateTimePickerCalendar;
     calendarBehavior.Calendar.ShowFooter = true;
     calendarBehavior.Calendar.ClearButton.Click += ClearButton_Click;
 }

 private void ClearButton_Click(object sender, EventArgs e)
 {
     this.radDateTimePicker1.DateTimePickerElement.SetToNullValue();
 }

Expose the AutoCompleteDropDown so it's behavior can be customized and the user can subscribe to its events for example.

You guys expose most of the properties from the "HostedControl" on your custom controls.  One that seems to be missing, and requires an unintuitive line of code is the "UseSystemPasswordChar" boolean property from the TextBox.  I think it makes a lot of sense to expose this.

See: http://www.telerik.com/forums/usesystempasswordchar-property-for-radtextbox

Add the ability to gain focus and change the toggle state upon keypress.
Add the ability to show the calendar with a key combination like Alt + DownArrow.

Add a possibility to suggest misspelled words if they are all capital letters or contains numbers.