Local $aktiv = True
    Local $arControl[8]

    $GUI = GUICreate('Titel')
    $arControl[0] = GUICtrlCreate...
    $arControl[1] = GUICtrlCreate...
    $arControl[2] = GUICtrlCreate...
    $arControl[3] = GUICtrlCreate...
    $arControl[4] = GUICtrlCreate...
    $arControl[5] = GUICtrlCreate...
    $arControl[6] = GUICtrlCreate...
    $arControl[7] = GUICtrlCreate... ; Button
    ;...
    If $msg = $arControl[7] Then _SwitchActiv()
    ;...
    Func _SwitchActiv()
        Local $state
        If $aktiv Then
            $state = $GUI_DISABLE
        Else
            $state = $GUI_ENABLE
        EndIf
        $aktiv = Not $aktiv
        For $i = 0 To 6
            GUICtrlSetState($arControl[$i], $state)
        Next
    EndFunc ; ==>_SwitchActiv

While 1

WEnd