B4J Question Problem triggering event of view array [solved]

#Region Project Attributes
    #MainFormWidth: 600
    #MainFormHeight: 200
#End Region

Sub Process_Globals
    Private fx As JFX
    Private MainForm As Form
    Private cb(), CheckBox1, CheckBox2, CheckBox3, CheckBox4 As CheckBox
End Sub

Sub AppStart (Form1 As Form, Args() As String)
    MainForm = Form1
    MainForm.RootPane.LoadLayout("main") 'Load the layout file.
    MainForm.Show
    cb = Array As CheckBox( CheckBox1, CheckBox2, CheckBox3, CheckBox4)
End Sub

'Return true to allow the default exceptions handler to handle the uncaught exception.
Sub Application_Error (Error As Exception, StackTrace As String) As Boolean
    Return True
End Sub

Sub cb_Click
    Dim i As Int
    Dim c As CheckBox
    c = Sender
    For i=0 To cb.Length-1
        cb(i).checked = False
    Next
    cb(c.Tag).Checked = True
End Sub