VERSION 5.00
Begin VB.UserControl ucMyBox 
   ClientHeight    =   450
   ClientLeft      =   0
   ClientTop       =   0
   ClientWidth     =   1140
   ScaleHeight     =   450
   ScaleWidth      =   1140
   Begin VB.TextBox txtMyBox 
      Height          =   405
      Left            =   0
      TabIndex        =   0
      Text            =   "Text1"
      Top             =   0
      Width           =   1095
   End
End
Attribute VB_Name = "ucMyBox"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = True
Attribute VB_PredeclaredId = False
Attribute VB_Exposed = True

Public Sub txtMyBox_LostFocus()
    txtMyBox.Tag = txtMyBox.Text & "Test"
End Sub