The reason there is space there is that you are using the OutlookExpress ViewStyle, under which the expansion indicator appears within cells of the the leftmost column whose data type is string. The space is there regardless of whether there is an expansion indicator because otherwise they would not all be aligned properly.

You can set the CanShowExpansionIndicator property to false for all columns if you want to prevent them from appearing altogether.

Hi Brian,

Thanks for the reply. I solved the problem with image not displaying on the nodes. But I still can't figure out why the text of the two columns is displayed differently using the same configuration. Later I found that when I comment out the datatype of "Index" column, the text is finally displayed correctly but this doesn't happen to "Value" column. Any idea?

Thanks.

    Private Sub Initialize()

        Dim rootColumnSet As UltraTreeColumnSet = uTree.ColumnSettings.RootColumnSet
        rootColumnSet.Columns.Clear()

        With uTree
            .DisplayStyle = UltraTreeDisplayStyle.Standard
            .ViewStyle = ViewStyle.OutlookExpress
            .FullRowSelect = True
            .HideSelection = False
            .ExpansionIndicatorSize = New Size(0, 0)
            .ScrollBounds = ScrollBounds.ScrollToLastItem
            .SelectionBehavior = UltraWinTree.SelectionBehavior.ExtendedAcrossCollections

            With .ColumnSettings
                .BorderStyleCell = UIElementBorderStyle.Solid
                .AutoFitColumns = AutoFitColumns.ResizeAllColumns
                .CellAppearance.BorderColor = SystemColors.Control
                .HeaderStyle = HeaderStyle.WindowsVista

                With .ColumnHeaderAppearance
                    .BorderColor = Color.Silver
                End With
            End With

        End With

        _IndexColumn = rootColumnSet.Columns.Add("Index")
        With _IndexColumn
            .Text = "Index"
            '.DataType = GetType(String)
            .LayoutInfo.PreferredCellSize = New Size(CInt(Me.Width / 2), 22)
            .AllowSorting = DefaultableBoolean.True
            .ShowSortIndicators = DefaultableBoolean.True
            .TipStyleCell = TipStyleCell.Show
        End With

        _ValueColumn = rootColumnSet.Columns.Add("Value")
        With _ValueColumn
            .Text = "Value"
            .DataType = GetType(String)
            .LayoutInfo.PreferredCellSize = New Size(CInt(Me.Width / 2), 22)
            .AllowSorting = DefaultableBoolean.True
            .ShowSortIndicators = DefaultableBoolean.True
            .TipStyleCell = TipStyleCell.Show
        End With

    End Sub