Clipboard gets emptied when VBA runs

Hi,

In my production workbook I've got code similar to the following excerpt:

'==============================================================================
' WORKSHEET ACTIVATION
'==============================================================================
' The actual event routines must be in a standard module for "Application.Run" to work properly
Private Sub Wkb_SheetActivate(ByVal Sh As Object)
    Select Case Sh.Name
        Case "MemberInfo"
            MemberInfo_Activate Sh
        Case "Cases"
            Cases_Activate Sh
        Case "Claims"
            Claims_Activate Sh
        Case "Letters"
            Letters_Activate Sh
        Case "Payments"
            Payments_Activate Sh
        Case "Money"
            Money_Activate Sh
        Case "FutureMedical"
            FutureMedical_Activate Sh
        Case "Notes"
            Notes_Activate Sh
        Case "Lawyers"
            Lawyers_Activate Sh
        Case "CaseSummary"
            CaseSummary_Activate Sh
        Case "CaseDetails"
            CaseDetails_Activate Sh
        Case "CaseHistory"
            CaseHistory_Activate Sh
        Case "Dashboard"
            Dashboard_Activate Sh
        Case "Lookups"
            Lookups_Activate Sh
        Case Else
            ' MsgBox Sh.Name & " is an unknown worksheet name.  Please see your Midas Administrator."
            ' Nothing...
    End Select
End Sub

Private Sub Money_Activate(ByVal Sh As Object)
    ProtectWorksheet
    Application.Calculate
End Sub

' Protect only if not already protected.
' RUNNING THE PROTECT METHOD CLEARS THE CLIPBOARD,
' MAKING IT IMPOSSIBLE TO PASTE INTO THIS WORKSHEET.
Sub ProtectWorksheet()
    With ActiveSheet
        If Not .ProtectContents Then  ' DO NOT REMOVE THIS LINE!!!
            .Protect _
                Password:="", _
                AllowSorting:=True, _
                AllowFiltering:=True, _
                UserInterFaceOnly:=True
            .EnableSelection = xlNoRestrictions
        End If  ' DO NOT REMOVE THIS LINE!!!
    End With
End Sub

So, in most cases, activating a worksheet re-protects the worksheet (UserInterfaceOnly) if it's not already protected. Note: the protection is just meant to keep the end user from shooting him/herself in the foot. There is no password on the worksheet protection; the end user can unprotect the worksheet if needed.

I thought conditionally executing the protection would keep the clipboard intact, but this doesn't appear to be the case.

What's irritating the end user is the inability to copy a cell value from one worksheet to another, in particular to the Money tab. When he clicks on the Money tab, the worksheet gets re-protected (if necessary), and the formulas are re-calculated. At which point the clipboard is empty, and he can't copy into the Money worksheet.

Why does executing VBA clear the clipboard - surely Microsoft could fix this??? Is there any workaround for this issue short of re-architecting my application?

Thanks,
Scott

P.S.: The reason it's coded this way is the vast bulk of the code is in a class module in an XLAM add-in. This approach was the only way I could get it to work. It's klunky but functional (and ultimately off-topic to my main question).