UserForm Textbox freezes on first try only

[03856me]

Excel 2007 - UserForm
From my main menu which is simply shapes with macros attached I launch the userform. Upon the first try, and not always, just sometimes, when I get to txt_vc1, it freezes and I am not allowed to move to the next textbox. I can still use my Exit button on the UserForm to unload the form and then go back in the same way and it works. Could someone help point me to what might be happening please?

Here is the code associated with the userform and textbox that is causing the problem.

Macro to Load UserForm

Sub EnterEdit()
    Frm_Input.Show False
End Sub

UserForm Initialize Code

Private Sub UserForm_Initialize()
     Worksheets("data").Visible = True
     Worksheets("data").Select
     Range("A" & Rows.Count).End(xlUp).Select
     ActiveSheet.Shapes("ReportMenu").Visible = False
     Worksheets("Main Menu").Visible = False
End Sub

TextBox Change Event Code

Private Sub txt_vc1_change()
     If txt_vc1.Value > 0 Then
          Me.cmd_addVC.Visible = False
          Me.lbl_vc2.Visible = True
          Me.txt_vc2.Visible = True
     End If
End Sub

TextBox Enter Exit Event Code

Private Sub txt_vc1_Enter()
    txt_vc1.BackColor = &HC0C0C0
End Sub
 
Private Sub txt_vc1_Exit(ByVal Cancel As MSForms.ReturnBoolean)
    txt_vc1.BackColor = &HFFFFFF
Select Case IsValidID(txt_vc1)
          Case True
                Me.lbl_VCnote.Visible = False
                Exit Sub
          Case Else
                txt_vc1.BackColor = &HFFFFFF
                Me.lbl_VCnote.Visible = True
                Beep
                Me.txt_vc1.SetFocus
                Me.cmd_addVC.Visible = False
                Me.cmd_add.Visible = False
                Me.cmd_addNegative.Visible = False
                Me.txt_vc2.Visible = False
                Me.lbl_vc2.Visible = False
                Cancel = True
      End Select
End Sub

IsValidID Function Code

  Function IsValidID(sID) As Boolean
      IsValidID = False
      sID = CStr(sID)
      If Not sID Like "########" Then Exit Function
      Select Case Mid(sID, 1, 2)
          Case 11 To 19, 21 To 39, 31 To 39, 99 To 99
          Case Else
              Exit Function
      End Select
      Select Case Mid(sID, 3, 2)
          Case 10 To 40
          Case Else
              Exit Function
      End Select
      Select Case Mid(sID, 5, 2)
          Case 3 To 60
              IsValidID = True
          Case Else
              Exit Function
      End Select
      IsValidID = True
  End Function

Thanks in Advance for Your Help!

 

[03856me]

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