Inconsistent error when moving worksheet - vba

Question

The code below is a function to move a worksheet in a workbook. It gets called from a userform that contains a listbox that lists the worksheets in the workbook. The input is an integer that gives the direction which to move the sheet. Left/right in workbook is up/down in the userform listbox, and the userform has up and down buttons that calls the function with different input (+1 for moving right and -2 for moving left).
This function sometimes gives the error Method 'Move' if object '_Worksheeet' failed, but not consistently. Mostly the error comes when moving a sheet a second time, so that I am not able to move a sheet more than once. Once the error occurs I am not able to move the sheet again. I can, however, select a different sheet and move this once before the same thing occurs.
If I implement a message box in the error handling, the behaviour changes. After closing the message box upon error, I can proceeed to move the same sheet again after an error. With a message box I can therefore move a sheet as many times as I want, but it only moves on every other button press. I guess the message box breaks code execution, which for some reason makes the function work again even one the same sheet that gave the error. I have tried replacing the message box with a delay or a selfclosing infobox but this does not give the same result.
To further complicate matters, sometimes when I open the userform application, the move buttons work perfectly without any error. I think this happens when the worksheet is already open before the application is opened.
It all seems very inconsistent, and beyond my knowledge. Any help or suggestions much appreciated.
Function FlyttMåling(Retning As Integer) As Boolean
Application.EnableEvents = False
Application.ScreenUpdating = False
'code to reference the correct workbook based on outside parameters
Dim wb As Workbook, ws As Worksheet
FlyttMåling = True
If Hovedvindu.LuftlydKnapp.Value = True Then
Set wb = ÅpneBok(1)
ElseIf Hovedvindu.TrinnlydKnapp.Value = True Then
Set wb = ÅpneBok(2)
End If
'sets variable to the index of sheet to be moved, chosen from list in userform
Dim nummer As Integer
Set ws = wb.Sheets(1)
If Hovedvindu.MålingerFrame.Liste.ListIndex < 0 Then
Exit Function
Else
Set ws = wb.Sheets(Hovedvindu.MålingerFrame.Liste.Value)
End If
nummer = ws.Index
'exit function if trying to move first sheet to the left or last sheet to the right
If (Retning = 1 And nummer = wb.Sheets.count) Or (Retning = -2 And nummer = 2) Then
Exit Function
End If
'code that moves worksheet
ws.Activate
On Error GoTo errHandler:
errResume:
ws.Move after:=wb.Sheets(nummer + Retning) 'THIS LINE CAUSES ERROR
On Error GoTo 0
Call oppdaterListe
'reselect the moved worksheet in the userform list
For i = 0 To Hovedvindu.MålingerFrame.Liste.ListCount - 1
If ws.Name = Hovedvindu.MålingerFrame.Liste.List(i) Then
Hovedvindu.MålingerFrame.Liste.Selected(i) = True
Exit For
End If
Next i
Application.EnableEvents = True
Application.ScreenUpdating = True
Exit Function
'error handling just sets the return to false to notify failure to move sheet
errHandler:
FlyttMåling = False
End Function

Answer 1

Found a workaround for this problmem. Changing the wb.move to a wb.copy, and then deleting the old sheet and renaming the copy to the name of the original sheet makes this code work as intended.