UltraGrid Edit Mode Is Not Being Entered

I asked a similar question (Well, indentical, in honesty) back in September, but the solution to that issue is, for some reason, not working in my latest incident...

My UltraGrid is being used now to enter the date of payment for each line in the order, and has a CheckBox column to mark it as paid. When each order line is paid for, the order progresses to the next stage.

Anyway, when the test order that I created is marked as delivered, and reaches the current stage (Stage 5 - Awaiting Customer Payment), I am initially able to edit the payment date and CheckBox column on each order line.

However, if I mark one as paid, and leave the other one blank and then save it, the following issue arises.

I go into the order to mark the next line as paid for. I am able to enter a date of payment, but not set the CheckBox to True. In fact, after stepping through it, the cell doesn't even enter EditMode, as the CellChange event is not triggered.

The code in CellChange below is supposed allow the CheckBox cell to be set to True once a date has been entered - However, it isn't entering Edit Mode.

Can anybody see why this would be?

 Try
        If e.Cell.Column.Key = "PaymentDate" Then
            e.Cell.Row.Cells("Customer_Paid").Activation = Activation.AllowEdit
            e.Cell.Row.Cells("Customer_Paid").IsInEditMode = True
        End If
    Catch ex As Exception
        errorLog(ex)
    End Try

    Try
        If e.Cell.Column.ToString = "Customer_Paid" Then
            Dim customerPaid As Boolean = Boolean.Parse(e.Cell.Text)

            If customerPaid = True Then
                If IsDBNull(ugProducts.ActiveRow.Cells("PaymentDate").Value) Then
                    MsgBox("Please enter a payment date", MsgBoxStyle.OkOnly, "Invalid Date")
                    e.Cell.Row.Cells("Customer_Paid").Value = False
                    ugProducts.ActiveRow.Appearance.BackColor = Color.White
                    ugProducts.ActiveRow.Cells("PaymentDate").Value = DBNull.Value
                Else
                    ugProducts.ActiveRow.Appearance.BackColor = Color.LightGreen
                    ugProducts.ActiveRow.Cells("Product_Price_Per").Appearance.BackColor = Color.LightGreen
                End If

                e.Cell.Row.Update()

            Else
                ugProducts.ActiveRow.Appearance.BackColor = Color.White
                ugProducts.ActiveRow.Cells("Product_Price_Per").Appearance.BackColor = Color.LightGreen
                ugProducts.ActiveRow.Cells("PaymentDate").Value = DBNull.Value
                Exit Sub
            End If
        Else

        End If

    Catch ex As Exception
        errorLog(ex)

    End Try

There are no errors, it just doesn't enter the EditMode state.

The solution with the previous case was to use the Boolean.Parse line that I've added this time around, yet it is unsuccessful this time.

Not the fix to the issue as such, but a way I got around it...

I changed the PaymentDate entry from allowing EditMode, to just setting the CheckBox to True.

The end user may not want it done this way, however, so question may still be unanswered, but just for now, this works.

If e.Cell.Column.Key = "PaymentDate" Then
   e.Cell.Row.Cells("Customer_Paid").Activation = Activation.AllowEdit
   e.Cell.Row.Cells("Customer_Paid").Value = True
End If