MS Access continuous form bound checkbox

I have a situation where i need to set only one ID as default on a continuous form. It does not seem to be easy to do so. Pls have a look on attached image, it is allowing me to choose more than one. I have tried with radio button, it does not work either

You can loop the RecordsetClone of the form:

Private Sub IsDefault_AfterUpdate()

    Dim rs  As DAO.Recordset
    
    If Me.Dirty Then
        Me.Dirty = False
    End If
    
    If Me!IsDefault.Value = True Then
        ' Deselect other records.
        Set rs = Me.RecordsetClone
        rs.MoveFirst
        While Not rs.EOF
            If rs!Id.Value <> Me!Id.Value Then
                If rs!IsDefault.Value = True Then
                    rs.Edit
                        rs!IsDefault.Value = False
                    rs.Update
                End If
            End If
            rs.MoveNext
        Wend
        rs.Close
        
        Me!SomeOtherControl.SetFocus
        Me!IsDefault.Enabled = False
        Me!IsDefault.Locked = True
    End If
    
End Sub

Private Sub Form_Current()

    Dim Ready           As Boolean
    Dim NewRecord       As Boolean
    
    NewRecord = Me.NewRecord
    
    If NewRecord Then
        Me!IsDefault.DefaultValue = Not CBool(Me.RecordsetClone.RecordCount)
        Me!SomeOtherControl.SetFocus
    Else
        Ready = Not Me!IsDefault.Value
    End If
    
    ' The selected record cannot be deselected.
    ' Deselect by selecting another record.
    Me!IsDefault.Enabled = Ready
    Me!IsDefault.Locked = Not Ready
    
End Sub