ok ... for someone like me that likes detailed solutions 

1-go to [YOUR PROJECT PATH]\App_Plugins\u7dtg\propertiesViews

2-Open rte.html

3- add this after (after is important) .. blablabla  </button> 

<script type="text/javascript" charset="UTF-8">
    $(document).on('focusin', function (e) {
        if ($(event.target).closest(".mce-window").length) {
            e.stopImmediatePropagation();
        }
    });
</script>

thank you 

AS