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.