Set the column to Sparse = .F.
Because you want normal date mark for not empty,
add another your class textbox to the column
column
txtNormal
txtEmpty <=== this have DateMark
set
column.DynamicCurrentcontrol="IIF(EMPTY(datefield),'txtEmpty','txtNormal')"
you can build a TxtDate and on Init(),
add the txtEmpty and set DynamicCurrentcontrol to the Column.
Fabio