William, your answer is a bald faced lie.
The HTT program adds a registry entry. Explorer does NOT do it.
And, it refreshes that entry when HTT runs so, simple deletion of the
"NullFile" value is useless.
This kind of behavior in an application program is inexcusable, bordering on
contemptable.

To permanently disable the desktop context menu "New" Whtt Project option.

HKEY_CLASSES_ROOT\.whtt\ShellNew

Delete the NullFile entry.
Right click on ".whtt" and select Permissions > Advanced.
Select a "Name" and Edit. Set permissions to Read Only (check "Deny" then,
uncheck "Query Value" and "Read Control"

Do this for all names including System.
Exit regedit - no more context menu litter.