\version "2.18.0"

pauseStaffBL = 
#(define-music-function (parser location white-width) (number?)
  (define (append-whitebox grob) 
    (let* (
      (stil (ly:bar-line::print grob))
      (yext (ly:stencil-extent stil 1))
      (y-padding 0.2)
      (box-height (interval-widen yext y-padding))
      (box-width (cons 0 white-width)) 
      (box-stil (make-filled-box-stencil box-width box-height))
      (whitebox-stil (stencil-with-color box-stil white
        )))
     (ly:stencil-combine-at-edge stil X RIGHT whitebox-stil 0)))
  #{
    \once \override Score.BarLine.stencil = #append-whitebox 
    \once \override Score.BarLine.layer = 1 % mask StaffSymbol
  #})