This is the VFP standard evaluation for a grid cell repaint:

IF cell.Value is null THEN EVAL(ObjCell.NullDisplay) <==== for me this is a internal bug

cell.Value = EVAL(ObjCell.ControlSource)

IF cell.Value is null THEN EVAL(objCell.NullDisplay) <==== this is correct

IF objCell.Alignment = Automatic
     dummyValue = cell.Value
     IF dummyValue IS NULL 
          dummyValue = EVAL(objCell.NullDisplay) <==== for me this is a not optimized code
     ENDIF
     cell.Alignment = _computeAlign(dummyValue)
ENDIF

VFPT can remove the useless first line evaluation.

Thanks

Fabio