Possibility to enter numbers with non-fixed number of digits after the decimal separator.
The SDK sample DynamicFormatString demonstrates such behavior.

Here is a link to it = > https://github.com/telerik/xaml-sdk/tree/master/MaskedInput/DynamicFormatString

We are marking this feature request as Declined - we won't introduce built-in logic for it. 

MaskedInput: The cursor of the Mouse is  Caret when it is over the built in ScrollViewer
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Reason for deletion: The bug is logged for RadMaskedTextBox and it will be removed from our suite from Q2 2014.

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

Supporting DateTimeOffset for DateTime masks

Add built in masks for Email, IP, Phone, etc. Add design time support for this.