Setting the Extnesions Minimum and Maximum values restricts the input of values that fall in the designated area but that start with a digit lesser than the minimum value. For example in the MaskedNumeric/CurrencyInput, if you set MaskedInputExtensions.Minimum="2" and MaskedInputExtensions.Maximum="20", you can't enter 12 unless the current value is 2 and the cursor is positioned before the 2 - only then you can insert the digit 1 before the digit 2 to create an input of 12.