There is no direct way to remove a custom form. It does no real harm to leave an obsolete form around. However, if you are determined, close SlickEdit, remove the forms from vusrobjs.e, and then "touch" vslick.sta in your installation directory. The newer date on the state file will trigger SlickEdit to migrate settings, and the forms should get wiped clean (since they are no longer in vusrobjs.e).