TMemoField.OnValidate Problem (does not fire)

We attempted to use the OnValidate event of a persistent TMemoField tied to
a databound TwwDBRichEdit control (Woll2Woll component), but the event does
not appear to fire.

We have had no problems using the OnValidate event with other persistent
fields, namely: TStringField, TSmallIntField, TDateTimeField, and
TIntegerField.

I realize that TMemoField (being a BLOB) is not placed in a table like other
fields, as the following quote from the help file suggests:

"Persistent field objects exist solely in the memory space of a Delphi
application. Creating a persistent field object only creates an object in
the application, and does not result in the creation of a field in a table."

But TMemoField does publish the OnValidate event. Does this TMemoField
actually fire, and if so, are there known circumstances that would prevent
it from firing? (There is nothing on the newsgroups that I have been able to
find that addresses this issue).