Border-Color
This property allows you to set or retrieve the border color of the Split-Pane control. See "Color management" for further details. The border color is applicable only to controls with the Boxed style.
 
Example - define a split-pane with red border
screen section.
...
  03 screen-1-sp-1 Split-Pane
     line 7.6
     column 5.8
     size 28.2 cells 
     lines 19.8 cells 
     border-color 5
     boxed
     .