for(pRow=p->pFirst; pRow; pRow=pRow->pNext){
    if( pRow->isDup ) continue;
    if( pRow->nParent<=0 ) continue;                   /* Root node */
    pParent = hashFind(p, pRow->aParent[0]);
    if( pParent==0 ) continue;                         /* Parent off-screen */
    if( pParent->zBranch!=pRow->zBranch ) continue;    /* Different branch */
    if( pParent->idx <= pRow->idx ){
       pParent->timeWarp = 1;
      pParent->timeWarp = 1;
       continue;                                       /* Time-warp */
    }
    if( pRow->idxTop < pParent->idxTop ){
    }else if( pRow->idx < pParent->idx ){
      pParent->pChild = pRow;
      pParent->idxTop = pRow->idxTop;
    }
  }

  if( tmFlags & TIMELINE_FILLGAPS ){
    /* If a node has no pChild but there is a node higher up in the graph
    ** that is in the same branch and that other node has no parent in
    ** the graph, the lower node a step-child of the upper node.  This will
    ** be represented on the graph by a thick dotted line without an arrowhead.
    */
    for(pRow=p->pFirst; pRow; pRow=pRow->pNext){
      if( pRow->pChild ) continue;
      for(pLoop=pRow->pPrev; pLoop; pLoop=pLoop->pPrev){
        if( pLoop->nParent>0
         && pLoop->zBranch==pRow->zBranch
         && hashFind(p,pLoop->aParent[0])==0
        ){
          pRow->pChild = pLoop;
          pRow->idxTop = pLoop->idxTop;
          pRow->isStepParent = 1;
          pLoop->aParent[0] = pRow->rid;
          break;
        }
      }
    }
  }

  /* Set the idxTop values for all entries.  The idxTop value is the
  ** "idx" value for the top entry in its stack of children.
  */
  for(pRow=p->pFirst; pRow; pRow=pRow->pNext){
    GraphRow *pChild = pRow->pChild;
    if( pChild && pRow->idxTop>pChild->idxTop ){
      pRow->idxTop = pChild->idxTop;
    }
  }

  /* Identify rows where the primary parent is off screen.  Assign
  ** each to a rail and draw descenders downward.
  **
  ** Strive to put the "trunk" branch on far left.
  */
  zTrunk = persistBranchName(p, "trunk");
  for(i=0; i<2; i++){
    for(pRow=p->pLast; pRow; pRow=pRow->pPrev){
      if( i==0 && pRow->zBranch!=zTrunk ) continue;
      if( pRow->iRail>=0 ) continue;
      if( pRow->isDup ) continue;
      if( pRow->nParent<0 ) continue;
      if( i==0 ){
        if( pRow->zBranch!=zTrunk ) continue;
      }else {
        if( pRow->iRail>=0 ) continue;
      }
      if( pRow->nParent==0 || hashFind(p,pRow->aParent[0])==0 ){
        pRow->iRail = findFreeRail(p, pRow->idxTop, pRow->idx+RISER_MARGIN, 0);
        if( p->mxRail>=GR_MAX_RAIL ) return;
        mask = BIT(pRow->iRail);
        if( !omitDescenders ){
          int n = RISER_MARGIN;
          pRow->bDescender = pRow->nParent>0;