The features on this page are not activated unless the user has checked the box for "Change certain numbers to characters" on the Advanced control panel.
HTML writers usually enter Unicode characters by typing a numeric macro that begins with "&#" or "&#x" and ends with a semicolon, such as Tuấn for Tuấn. Here, the lower case letter ấ has a Unicode encoding value of 1EA5 in hexadecimal.
HTML requires that the &#x prefix be used with hexadecimal numbers and &# with decimal numbers and a semicolon suffix be used to end the number.
Thus WinVNKey provides this feature to make it possible for typing characters that you do not know how to enter via keyboard directly but do know their encoding values. This feature can be used to type Hán Nôm characters that are missing from the Han Nom database. You simply enter the HTML code and WinVNKey will convert it to the true Han Nom character on the fly.
The dialog is self-explanatory. Checking the check boxes on this dialog does not necessarily mean the feature is activated. You must have checked the checkbox for "Change certain numbers to characters" in the Advanced control panel.
By design, any change you make to this dialog will become effective immediately and will be saved to disk so that the same setting will be used for subsequent WinVNKey runs.