The IsDefaulted property is true when the IsDefault property is set to true and the control that has focus does not accept ENTER as input. For example, in the Run dialog box, the OK button is the default button. When focus is on the text box, IsDefaulted on the OK button is true because a user can activate the button by pressing ENTER.
If the default button has focus, IsDefaulted is false. This is because the OnKeyDown method handles ENTER, and it is not necessary for IsDefaulted to be set to true.