private SessionDataDto defineCurrentSession(CellDoubleClickEvent event) {
   String sessionId =
       treeGrid.getColumnModel().getColumn(event.getCellIndex()).getHeader().asString();
   String sessionData_id = sessionId.substring(sessionId.indexOf(' ') + 1);
   SessionDataDto currentSession = null;
   for (SessionDataDto sessionDataDto : SessionComparisonPanel.this.chosenSessions) {
     if (sessionDataDto.getSessionId().equals(sessionData_id)) {
       currentSession = sessionDataDto;
       break;
     }
   }
   return currentSession;
 }
 // // to make columns fit 100% width if grid created not on Summary Tab
 public void refresh() {
   treeGrid.getView().refresh(true);
 }
  private void init(Set<SessionDataDto> chosenSessions, int width) {

    int colWidth = calculateWidth(chosenSessions.size(), width);

    treeStore.clear();
    List<ColumnConfig<TreeItem, ?>> columns = new ArrayList<ColumnConfig<TreeItem, ?>>();

    // sort sessions by number sessionId
    SortedSet<SessionDataDto> sortedSet =
        new TreeSet<SessionDataDto>(
            new Comparator<SessionDataDto>() {
              @Override
              public int compare(SessionDataDto o, SessionDataDto o2) {
                return (Long.parseLong(o.getSessionId()) - Long.parseLong(o2.getSessionId())) > 0
                    ? 1
                    : -1;
              }
            });
    sortedSet.addAll(chosenSessions);

    ColumnConfig<TreeItem, String> nameColumn =
        new ColumnConfig<TreeItem, String>(
            new MapValueProvider(NAME), (int) (colWidth * METRIC_COLUMN_WIDTH_FACTOR));
    nameColumn.setHeader(METRIC);
    nameColumn.setSortable(false);
    nameColumn.setMenuDisabled(true);
    columns.add(nameColumn);

    for (SessionDataDto session : sortedSet) {
      ColumnConfig<TreeItem, String> column =
          new ColumnConfig<TreeItem, String>(
              new MapValueProvider(SESSION_HEADER + session.getSessionId()));
      column.setHeader(SESSION_HEADER + session.getSessionId());
      column.setWidth(colWidth);
      column.setSortable(false);
      column.setCell(
          new AbstractCell<String>() {
            @Override
            public void render(Context context, String value, SafeHtmlBuilder sb) {
              if (value != null) {
                sb.appendHtmlConstant(value);
              }
            }
          });
      column.setMenuDisabled(true);

      column.setColumnTextStyle(
          new SafeStyles() {
            @Override
            public String asString() {
              return WHITE_SPACE_NORMAL;
            }
          });

      columns.add(column);
    }

    ColumnModel<TreeItem> cm = new ColumnModel<TreeItem>(columns);

    treeGrid = new NoIconsTreeGrid(treeStore, cm, nameColumn);

    treeGrid.addBeforeCollapseHandler(
        new BeforeCollapseItemEvent.BeforeCollapseItemHandler<TreeItem>() {
          @Override
          public void onBeforeCollapse(BeforeCollapseItemEvent<TreeItem> event) {
            event.setCancelled(true);
          }
        });

    treeGrid.setAutoExpand(true);
    treeGrid.getView().setStripeRows(true);
    treeGrid.setMinColumnWidth(MIN_COLUMN_WIDTH);
    treeGrid.setAllowTextSelection(true);
    treeGrid.getView().setForceFit(true);

    treeStore.addStoreAddHandler(
        new StoreAddEvent.StoreAddHandler<TreeItem>() {
          @Override
          public void onAdd(StoreAddEvent<TreeItem> event) {
            for (TreeItem item : event.getItems()) {
              treeGrid.setExpanded(item, true);
            }
          }
        });

    if (webClientProperties.isUserCommentEditAvailable()) {
      treeGrid.addCellDoubleClickHandler(
          new CellDoubleClickEvent.CellDoubleClickHandler() {
            @Override
            public void onCellClick(CellDoubleClickEvent event) {
              TreeItem item =
                  treeGrid.findNode(treeGrid.getTreeView().getRow(event.getRowIndex())).getModel();
              if (item.getKey().equals(USER_COMMENT) && event.getCellIndex() > 0) {
                SessionDataDto currentSession = defineCurrentSession(event);
                userCommentBox.popUp(
                    currentSession, item.get(SESSION_HEADER + currentSession.getSessionId()), item);
              }
            }
          });
    }

    if (webClientProperties.isTagsAvailable()) {
      treeGrid.addCellDoubleClickHandler(
          new CellDoubleClickEvent.CellDoubleClickHandler() {
            @Override
            public void onCellClick(CellDoubleClickEvent event) {
              TreeItem item =
                  treeGrid.findNode(treeGrid.getTreeView().getRow(event.getRowIndex())).getModel();
              if (item.getKey().equals(SESSION_TAGS) && event.getCellIndex() > 0) {
                SessionDataDto currentSession = defineCurrentSession(event);
                if (allTagsLoadComplete) tagBox.popUpForEdit(currentSession, item, allTags);
              }
            }
          });
    }

    add(treeGrid);
  }