I am not sure what the NODEFAULT does in the case you mention.

In the keyPress, it supresses the native VFP handling of the keyStroke. For example, if it is a printable character, the native behavior is to echo it to the screen. If it is a navigation key, like TAB, DNARROW, etc. the native behavior is to move to the next object in the TAB order. So, if you set focus to something that is not the next object in the tab order, the NODEFAULT keeps VFP from setting focus to the object you specified and then immediately setting forcus to the next object in the tab order.