Width-In-Cells
This style implies that the value specified for the Size property, the one setting the Date-Entry control’s width, is expressed in CELLS. It is possible to get the same result writing: "Size value CELLS".
 
Example - Define a date-entry control that shows the week of the year on the calendar area
screen section.
...
  03 screen-1-de-2 Date-Entry
     line 28.5
     column 49.7
     size 13.6
     lines 4.3 cells 
     id 18
     width-in-cells.