Is there any easy way to make this change in my grid baseclass?

I am pretty sure that this bug was fixed in version 7, but I could be wrong. If you need to use this workaround in version 6, I supposed you could add code like this to the grid's valid() (untested and off the top of my head < s > )

llRetVal = .T.
FOR EACH loColumn IN This.Columns
  FOR EACH loControl IN loColumn.Controls
    IF PEMSTATUS( loControl, [Valid], 5 )
      llRetVal = llRetVal AND loControl.Valid()
    ENDIF
  ENDFOR
ENDFOR
RETURN llRetVal

Of course, this code assumes that all the valid methods of the contained controls return a logical value. If they return numeric values, obviously you must modify the code.