This variable is used on character-based hosts to specify the color and video attributes of the characters that form the border (box) around an inactive floating window. INACTIVE__BORDER__COLOR can be set to a variety of numeric values that express combinations of color and video attributes. See the documentation for the COLOR phrase in the "Common Screen Options" section of the Reference Manual (section 6.4.9).
If INACTIVE_BORDER_COLOR is set to "0", the inactive window's border is drawn with the colors and video attributes specified in the COBOL program when the window is first created. The default value is "0".