There’s nothing in the customization window to delete a form event that was created with the Form Event Wizard.
Do I just go to the Script editor and delete the function, and the calls in InitializeCustomCode() and DestroyCustomCode()? That’s simple enough, but there are the warnings:
// Do not delete 'Begin/End Wizard Added Variable Initialization' lines **
The safest thing would be to hollow out the generated function (so it does nothing), and leave it, the create call, and the destroy call alone. But that seems kind of sloppy.