Private Sub FormularClosing(ByVal sender As Object, _
    ByVal e As System.Windows.Forms.FormClosingEventArgs) Handles Me.FormClosing
 
        'Falls der User das Formular schließt ....
        If e.CloseReason = CloseReason.UserClosing Then
            Me.Hide() 'Verstecken
            e.Cancel = True 'Vorgang des Schließens abbrechen
        End If
    End Sub