Collapsed rows give unexpected results in a grid

Question

Hi,
For learning purposes, I am working on the sample which comes with SDK called: 19.Grid.
I have modified the basic sample as follows:
I have added a checkbox column
I have added code to color the row which is ticked. It ticked = blue, if unticked = gray
I retained only 2 collapse levels:
CollapseLevel = 0 for the radiobutton "No Grouping"
CollapseLevel = 1 for the radiobutton "Card Code"
The relevant code I used is shown at the bottom of this thread.
oGrid.CommonSetting.SetRowBackColor(pVal.Row + 1, newColor)
When I group on Card Code and Expand all rows, the code for background color works fine:
When I tick any checkbox, the row becomes blue.
When I untick the checkbox, the row returns to gray.
No problem at all here..
Problem:
Problems arise when some rows are collapsed.
The attached picture explains the problem better than words.
It seems that when there are collapsed rows ABOVE the relevant checkbox, then pVal.Row is not working properly.
If I expand all rows, the rows are correctly colored when I tick a checkbox.
Request:
Anybody knows what is happening, and propose a solution?
Thanks
Leon Lai
Picture:
Relevant Code: (in SBO_Application > ItemEvent)
Private Sub SBO_Application_ItemEvent(ByVal FormUID As String, ByRef pVal As SAPbouiCOM.ItemEvent, ByRef BubbleEvent As Boolean) Handles SBO_Application.ItemEvent
        BubbleEvent = True
        Dim EventEnum As SAPbouiCOM.BoEventTypes
        EventEnum = pVal.EventType
        If (FormUID = "frmGrid") And ((pVal.ItemUID = "optNo") Or _
             (pVal.ItemUID = "optCode")) And _
             (pVal.EventType = SAPbouiCOM.BoEventTypes.et_ITEM_PRESSED) And (pVal.BeforeAction = False) Then
            If (userDS.Value = 1) Then
                oForm.Freeze(True)
                DocStatus, U_HandOver, ShipToCode from OINV where U_HandOver IS NULL and ShipToCode NOT LIKE  '%Address' ")
                oForm.DataSources.DataTables.Item(0).ExecuteQuery("Select TOP 3000 CardCode, CardName, DocDate, DocEntry, DocNum, DocTotal,                     DocStatus, U_HandOver, ShipToCode from OINV where U_HandOver IS NULL ")
                oGrid.Columns.Item("U_HandOver").Type = SAPbouiCOM.BoGridColumnType.gct_CheckBox
                oGrid.CollapseLevel = 0
                oForm.Freeze(False)
            ElseIf (userDS.Value = 2) Then
                oForm.Freeze(True)
               oForm.DataSources.DataTables.Item(0).ExecuteQuery("Select TOP 3000 CardCode, CardName, DocDate, DocEntry, DocNum, DocTotal,                     DocStatus, U_HandOver, ShipToCode from OINV where U_HandOver IS NULL ")
                oGrid.Columns.Item("U_HandOver").Type = SAPbouiCOM.BoGridColumnType.gct_CheckBox
                oGrid.CollapseLevel = 1
                oForm.Freeze(False)
            End If
        End If
        If (FormUID = "frmGrid") And (pVal.BeforeAction = False) And _
       (pVal.EventType = SAPbouiCOM.BoEventTypes.et_CLICK) And _
       ((pVal.ItemUID = "btnCol") Or (pVal.ItemUID = "btnExp")) Then
            If (pVal.ItemUID = "btnCol") Then
                oGrid.Rows.CollapseAll()
            End If
            If (pVal.ItemUID = "btnExp") Then
                oGrid.Rows.ExpandAll()
            End If
        End If
        If FormUID = "frmGrid" And pVal.BeforeAction = False _
            And pVal.EventType = SAPbouiCOM.BoEventTypes.et_ITEM_PRESSED _
            And pVal.ColUID = "U_HandOver" Then
            Dim newColor As Integer = If(oGrid.DataTable.GetValue("U_HandOver", oGrid.GetDataTableRowIndex(pVal.Row)).ToString() = "Y", 16777088,           15198183)
            oGrid.CommonSetting.SetRowBackColor(pVal.Row + 1, newColor)
        End If

Answer 1

Hi Maik,
Thanks for your reply, but I'm still shrouded in mystery.
>> the value is set in the row before :
>> 1. row is leaf
>> 2.lastbranchExpanded = true
Do you mean this line?
Dim lastbranchExpanded As Boolean = True
Even if I set it = False, the code works perfectly!
Anyway, it is = True only initially.
If the row is a leaf, this value is set to = False, so it is no longer = True
If the row IS NOT a leaf, this code is executed:
If Not oGrid.Rows.IsLeaf(i) Then
                    lastbranchExpanded = oGrid.Rows.IsExpanded(i)
and it returns False.
Yes! Here lastbranchExpanded IS INDEED EVALUATED (to False)
But if the row IS a leaf, the above code IS NOT executed
and hence, there is nothing to set the value of lastbranchExpanded to True.
Notice that the initial value (True) has already changed to False.
Nowhere in your code is there something to set the value of lastbranchExpanded to True
Your code only says that if lastbranchExpanded  =True, then expandedleafs += 1
I still cannot see WHERE the value of lastbranchExpanded is set to TRUE in the first place.
Really,I am in thick mud. Hope you can enlighten me!
Best Regards,
Leon