Event Fired after Close

[JaedenRuiner]

So i've got several SplitContainer's on the form, and they all have their event set to a method: SplitterMoved() for purposes of saving the current layout of the form.
my method:

  Private Sub SplitContainer_SplitterMoved(ByVal sender As Object, ByVal e As System.Windows.Forms.SplitterEventArgs) _
                              Handles SplitterH_Tab1.SplitterMoved, SplitterV_Tables.SplitterMoved, SplitterH_Childs.SplitterMoved
      If (Not _Refreshing) AndAlso (_RexCon IsNot Nothing) AndAlso (Not Me.Disposing) Then
         Dim sc As SplitContainer = DirectCast(sender, SplitContainer)
         Dim layoutKey As String = Strings.Right(_RexCon.ActiveTable, _RexCon.ActiveTable.Length - 4)
         Console.WriteLine("SplitterMoved - " & sc.Name & ": " & e.SplitX & "x" & e.SplitY)
         If layoutKey.IsValid AndAlso _layout.HasKey(layoutKey) Then
           [B] _layout(nav_TablesCmb.Text)(sc.Name).GetCurrentValues()[/B]
         End If
      End If
   End Sub

the bolded line is import later. So I open my app, which initially displays the Login Form, which if successful, opens my MainForm.
The Mainform is crazily enough, the Main Application Form, from which i open other forms, specifically the AdminForm. Now when I close the AdminForm it doesn't specifically close it if the reason is for a userclosing, (ie via, menu, Form.Close(), or the X button on the form), it only hides it in those circumstance so that I can reload it quicky by simply listening to the VisibleChanged() event. This works fine.

here is the pattern for my error:

• Mainform Open
• Open AdminForm
• Close AdminForm
• Close MainForm (no Error)

• MainForm Open
• Open MainForm
• Close MainForm
• Halt on Error at Bolded Line : Object Cannot be Null

Now, basically it seems, that if in my mainform.closing method if I put in an AdminForm.Close() the error is abated. So once again the stupidity of a langauge design trying to think for the programmer has screwed everything up, because I can't help but wonder how can an event fire when the object that created it is being disposed? The Form is going bye-bye and yet i'm getting an event fired after-the-fact. Even the Disposing property says the address for the method is null so that doesn't work either. How can i prevent, no matter what, the event's from triggering when the form is being closed on the VB application side of things?
Thanks