private void setKeepTrailingSpacesOnCaretLine(@Nullable Boolean keepTrailingSpacesOnCaretLine) {
      if (keepTrailingSpacesOnCaretLine != null && myKeepTrailingSpacesOnCaretLine == null) {
        myKeepTrailingSpacesOnCaretLine = keepTrailingSpacesOnCaretLine;
      }
    }
private void setKeepTrailingSpacesOnCaretLine(@Nullable Boolean keepTrailingSpacesOnCaretLine)