After installing SP1, we have huge problems with a self-grown class
which inherits from Windows.Forms.Datagrid. It throws exceptions every
now and then, such as this:

System.NullReferenceException: Object reference not set to an instance
of an object.
-------
   at System.Data.DataTable.RecordStateChanged(Int32 record1,
DataViewRowState oldState1, DataViewRowState newState1, Int32 record2,
DataViewRowState oldState2, DataViewRowState newState2)
-------
   at System.Data.DataTable.SetNewRecord(DataRow row, Int32
proposedRecord, DataRowAction action, Boolean isInMerge)
-------
   at System.Data.DataRow.EndEdit()
-------
   at System.Data.DataRowView.EndEdit()
-------
   at System.Windows.Forms.CurrencyManager.EndCurrentEdit()
-------
   at System.Windows.Forms.CurrencyManager.ChangeRecordState(Int32
newPosition, Boolean validating, Boolean endCurrentEdit, Boolean
firePositionChange, Boolean pullData)
-------
   at System.Windows.Forms.CurrencyManager.set_Position(Int32 value)
-------
   at System.Windows.Forms.DataGrid.set_Item(Int32 rowIndex, Int32
columnIndex, Object value)
-------
   at
PRISMA.BOBJ.Client.ConnectedControls.MyDataGrid.UpdateNotConnectedColumns(Int32
vRowNum, GridDefinition vGridDefinition) in
c:\VSSLOCAL\BOBJ\Src\PRISMA.BOBJ.Client\ConnectedControls\ConnectedDataGrid.vb:line
1359
-------
   at
PRISMA.BOBJ.Client.ConnectedControls.ConnectedDataGrid.UpdateNotConnectedColumns()
in
c:\VSSLOCAL\BOBJ\Src\PRISMA.BOBJ.Client\ConnectedControls\ConnectedDataGrid.vb:line
490
-------
   at
PRISMA.BOBJ.Client.ConnectedControls.ConnectedDataGrid.FillGridWithData()
in
c:\VSSLOCAL\BOBJ\Src\PRISMA.BOBJ.Client\ConnectedControls\ConnectedDataGrid.vb:line
472
-------
   at
PRISMA.BOBJ.Client.ConnectedControls.ConnectedDataGrid.FillInputComponent()
in
c:\VSSLOCAL\BOBJ\Src\PRISMA.BOBJ.Client\ConnectedControls\ConnectedDataGrid.vb:line
282
-------
   at
PRISMA.BOBJ.Client.Bases.BaseLivingControlImplementation.RefreshData()
in
c:\VSSLOCAL\BOBJ\Src\PRISMA.BOBJ.Client\Bases\BaseLivingControlImplementation.vb:line
179
-------
   at
PRISMA.Alim2000.Zahlungserfassung.Panels.MyZahlungsZuteilungsDataGrid.RefreshData()
in
c:\VSSLOCAL\ALIM2000\Src\PRISMA.Alim2000.Lib\Zahlungserfassung\Panels\Panel_Zahlung.vb:line
2602
-------
   at
PRISMA.Alim2000.Zahlungserfassung.Panels.Zahlung.OnApplicationIdle(Object
vSender, EventArgs vEv) in
c:\VSSLOCAL\ALIM2000\Src\PRISMA.Alim2000.Lib\Zahlungserfassung\Panels\Panel_Zahlung.vb:line
349
-------
   at System.EventHandler.Invoke(Object sender, EventArgs e)
-------
   at
System.Windows.Forms.ThreadContext.System.Windows.Forms.UnsafeNativeMethods+IMsoComponent.FDoIdle(Int32
grfidlef)
-------
   at
System.Windows.Forms.ComponentManager.System.Windows.Forms.UnsafeNativeMethods+IMsoComponentManager.FPushMessageLoop(Int32
dwComponentID, Int32 reason, Int32 pvLoopData)
-------
   at System.Windows.Forms.ThreadContext.RunMessageLoopInner(Int32
reason, ApplicationContext context)
-------
   at System.Windows.Forms.ThreadContext.RunMessageLoop(Int32 reason,
ApplicationContext context)
-------
   at System.Windows.Forms.Application.Run(Form mainForm)
-------
   at PRISMA.Alim2000.WinApp.Main.Main() in
c:\VSSLOCAL\ALIM2000\Src\PRISMA.ALIM2000.WinApp\Main.vb:line 108

Before installing SP1, there was no problem whatsoever with this code.
Now more and more of our customers are installing SP1 because it is a
"critical update" on windowsupdate.com - and our application fails...
Not nice, Microsoft!!! Note that our custom datagrid class only uses
"allowed" methods of inheriting and overriding, no calling of private
methods via Reflection, or similar disallowed things! This MUST NOT
happen with a SP, it HAS TO BE 100 % compatible!

This is just to inform everyone of this problem. Now I'm going to have a
look into the code... hope I can still enjoy my weekend.

If anybody has a workaround or an idea where to look, I'd be very grateful.

Urs