John,

>In VFP6SP5, this prints .F. :)

because earlier versions of compobj do not handle null and the ox and oy objects both have null pointers for .Parent. In either 7 or 8 they changed compobj() to consider null == null for a property between the two tested objects.

>If it prints .T. in later versions, that's probably a better reason not to use it. :)

It all depends. Quite frankly I've never really found much use for this function.