Height-In-Cells
This style implies that the value specified for the 
Lines property, the one setting the Combo-Box control’s height, is expressed in CELLS. It is possible to get the same result writing: "
Lines value CELLS".
 
Example - Define a combo-box in screen section with height in cells
screen section. ...   03 screen-1-co-1 Combo-Box      line 19.0      column 23.0      size 12.0 cells       lines 11.0      id 13      3-d      drop-down      height-in-cells      .  |