u64 mask;
  int hasDup = 0;      /* True if one or more isDup entries */
  const char *zTrunk;
  u8 *aMap;            /* Copy of p->aiRailMap */
  int omitDescenders = (tmFlags & TIMELINE_DISJOINT)!=0;
  int nTimewarp = 0;
  int riserMargin = (tmFlags & TIMELINE_DISJOINT) ? 0 : RISER_MARGIN;
  int offPageMergeRail = -1;

  /* If mergeRiserFrom[X]==Y that means rail X holds a merge riser
  ** coming up from the bottom of the graph from off-screen check-in Y
  ** where Y is the RID.  There is no riser on rail X if mergeRiserFrom[X]==0.
  */
  GraphRowId mergeRiserFrom[GR_MAX_RAIL];

      pDesc = hashFind(p, parentRid);
      if( pDesc==0 ){
        int iMrail = -1;
        /* Merge from a node that is off-screen */
        if( iReuseIdx>=p->nRow+1 ){
          continue;  /* Suppress multiple off-screen merges */
        }

#if 1
        /* Display option #1 for off-page merge lines:
        **
        ** Use a single rail for all merge lines that go to the bottom of
        ** the page.
        */
        if( offPageMergeRail>=0 ){
          iMrail = offPageMergeRail;
        }else{
          iMrail = findFreeRail(p, pRow->idx, p->pLast->idx, 0, 1);
          if( p->mxRail>=GR_MAX_RAIL ) return;
          mergeRiserFrom[iMrail] = parentRid;
          offPageMergeRail = iMrail;
        }
#else
        /* Display option #2 for off-page merge lines:
        **
        ** Use separate rails for each distinct parent node that is
        ** off of the bottom of the page.
        */
        for(j=0; j<GR_MAX_RAIL; j++){
          if( mergeRiserFrom[j]==parentRid ){
            iMrail = j;
            break;
          }
        }
        if( iMrail==-1 ){
          iMrail = findFreeRail(p, pRow->idx, p->pLast->idx, 0, 1);
          if( p->mxRail>=GR_MAX_RAIL ) return;
          mergeRiserFrom[iMrail] = parentRid;
        }
#endif

        iReuseIdx = p->nRow+1;
        iReuseRail = iMrail;
        mask = BIT(iMrail);
        if( i>=pRow->nNonCherrypick ){
          pRow->mergeIn[iMrail] = 2;
          pRow->cherrypickDown |= mask;
        }else{