Hi,
The MaskedInput control features a MaskedInputExtensions class which allows further control customization. It can be accessed in XAML through the xmlns:maskedInput="clr-namespace:Telerik.Windows.Controls.MaskedInput;assembly=Telerik.Windows.Controls.Input" namespace. This class has a property which can be used to control the keyboard navigation - the IsEditorTabStop property.
Please, use this property as follows to exclude the control from the keyboard navigation:
<telerik:RadMaskedTextInput maskedInput:MaskedInputExtensions.IsEditorTabStop="False" />
Regards,
Vicky
Progress Telerik