May I know how to freeze a column in a grid.

In addition to what Cetin has said, if you want to lock only a single column, this code will do it for you:

Put this in the Init():

WITH This
  *** Find out which column is the leftmost column
  *** when the grid is instantiated and save it
  FOR lnCol = 1 TO .ColumnCount
    IF .Columns[ lncol ].ColumnOrder = 1
      .nFirstColumn = lnCol
      EXIT
    ENDIF
  ENDFOR
ENDWITH

This code in the Scrolled Method:

WITH This
  *** if we scrolled horizontally, adjust the column order
  *** so the leftmost column stays the leftmost column
  IF nDirection > 3
    .Columns( .nFirstColumn ).ColumnOrder = .LeftColumn
  ENDIF
ENDWITH

And this in AfterRowColChange:

WITH This
  *** if we scrolled horizontally, adjust the column order
  *** so the leftmost column stays the leftmost column
  IF .RowColChange > 1
    .Columns( .nFirstColumn ).ColumnOrder = .LeftColumn
  ENDIF
ENDWITH