twAttrib( wBorder, wColor, wT, wL, wB, wR )
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     Changes the colour attribute of all or part of the currently
     window active window. twAttrib() uses a 'C' routine with direct
     screen writes for speed.

       Arguments:

     Border  - 'L' Include or Exclude the border whether in a box or a
                   window. Defaults to .F.

     wColor  - 'C' Clipper colour attribute (eg., "R/GR*").  This
                   function takes no action if wColor is not passed.

     wT,wL
     wB,wR   - 'N' Relative Window Coordinates. This defaults to
                   display area for the current window if not passed.

       Return:

     Current window handle

       Example:

     twAttrib( .F., "W/R", 5, 5, 10, 10 )