Which Form Event.......??

I am trying to set a form so ALL text boxes return Proper case. I can get this to work by placing the code on each text box calling a function.....

Private Sub Text0_AfterUpdate()
Dim ctl As Control

For Each ctl In Controls

If ctl.Tag = "*" Then Call Proper

Next ctl

End Sub
``````````````````
the module is
```
Function Proper()
On Error GoTo Proper_Err

Screen.ActiveControl = StrConv(Screen.ActiveControl, 3)

Proper_Exit:
Exit Function

Proper_Err:
MsgBox Error$
Resume Proper_Exit

End Function
`````````````
What I am trying to get to is to have the text box event...Private Sub Text0_AfterUpdate() ...... Be a Form event... So the code would apply to every text box on the form.
Tried it on different form events..... Cant get it to work. Any ideas????

Thanks