>What exactly does the NODEFAULT statement do ?

as its name implies it prevents the defualt action from taking place e.g
let say u modified the keypress event of a textbox sub-class
and among other things you called the keypress event the
regular VFP txtbox [txtbox::keypress(key,altctrlshift)]
if u will not include the NODEFAULT the key will be processed
again (the effect will be as if u pressed the key twice)
including NODEFAULT will prevent the keypress event to continue
it normal course (after the code u added)