ValueMode feature is designed to format the resulting Value with /without literals and placeholders, depending on the values of all properties - Mask, Value, ValueMode, Placeholder.
This feature request should allow the initial value which user can set or bind, to already include literals placeholders. This way control should display , for example incomplete phone numbers:
For example: Mask ="###-####"
                        ValueMode=IncludeLiteralsAndPlacehodlers
                        Value="___-6789"
Control UI on load: "___-6789".
Currently the control will display "678-9___" in this scenario.

Provide a way to set .5 and display it like 0.5 , not 5.0 in No-Mask Numeric input.

Currently, the SpinMode logic tries to kick-in on MouseWheel, even if the control is not focused. This handles the event which causes unexpected behaviors in some cases. Do not handle the MouseWheel event when the focus is not within the masked input control. You can consider adding a mode that allows you disable the default behavior.

Support entering a single digit in a DateTimeMaskedInput control with Mask="MM"

Currently the MaskedInput controls cannot handle properly Chinese input symbols from Google Pinyin or MS IME.

MaskedInput's code relies on methods from TextBox which do not fire when the input is not from keyboard.

The method should be called after the text that should be copied to the clipboard is extracted. In its original implementation it should only set the text to the clipboard. You should be able to override it and replace the text or use different method for copying into the clipboard.

For example:
public class CustomMaskedInputControl : RadMaskedDateTimeInput
{
    protected override void SaveTextToClipboard(string text)
    {
        Clipboard.SetDataObject(text);
    }
}

MaskedInput's Value is bound to property of an Entity class. This property has EditableAttribute.

MaskedInput's will set IsReadOnly True if the EditableAttribute's AllowEdit is False.

Clients need mechanism to stop this validation in MaskedInput.

If a user has selected all text in a numeric masked input control with a decimal (eg. 12.34), if they start typing a new value with a period (eg user types .89), the integer potion of the decimal does not change (so the input control now displays 12.89 instead of 0.89). Please provide a way to clear out what's to the left of the decimal when users type the period, as this is much more inline with the expected behavior of pretty much any other input control. 

The user has selected all the text and started typing. There's no excuse for not clearing out all the text in the input control in this scenario. Our clients are rightfully frustrated with this behavior.

Currrently the default ContextMenu of the TextBox inside the MaskedInput is used. You have to set it to null in code behind and the create custom ContextMenu in XAML / Code behind to use it successsfully.

In MaskedTextInput, users need to enter from right to left just like in NumericInput and CurrencyInput.

Allow entering an input in (exponent) scientific notation form for the RadMaskedNumericInput control

Users sometimes need to invoke Undo / Redo. Public command properties would be a possible way to go.

Currently the MaskedInput controls cannot parse strings containing such full-width symbols.

Actually the .net framework also cannot directly parse such symbols.

Currently users are not allowed to completely remove or customize the Undo/Redo actions in the RadMaskedInput controls. Consider adding extensibility points such as commands or events.

Initially, when the value is 0, the mask control could look like - $__,___.00 instead of $__,___0.00.

Currently this property works only in MaskedTextInput.

Supporting DateTimeOffset for DateTime masks