**     "showArrowheads": BOOLEAN,   // True for arrowheads. False to omit
**     "iRailPitch": INTEGER,       // Spacing between vertical lines (px)
**     "colorGraph": BOOLEAN,       // True to put color on graph lines
**     "nomo": BOOLEAN,             // True to join merge lines with rails
**     "iTopRow": INTEGER,          // Index of top-most row in the graph
**     "omitDescenders": BOOLEAN,   // Omit ancestor lines off bottom of screen
**     "fileDiff": BOOLEAN,         // True for file diff. False for check-in
**     "scrollToSelect": BOOLEAN,   // Scroll to selection on first render
**     "nrail": INTEGER,            // Number of vertical "rails"
**     "baseUrl": TEXT,             // Top-level URL
**     "rowinfo": ROWINFO-ARRAY }
**
** The rowinfo field is an array of structures, one per entry in the timeline,
** where each structure has the following fields:
**

      renderGraph();
      lastY = h;
    }
    setTimeout(checkHeight, 1000);
  }
  initGraph();
  checkHeight();
  if( tx.scrollToSelect ){
    scrollToSelected();
  }

  /* Set the onclick= attributes for elements of the "Compact" display
  ** mode so that clicking turns the details on and off.
  */
  var lx = topObj.getElementsByClassName('timelineEllipsis');
  var i;
  for(i=0; i<lx.length; i++){