diff --git a/lib/mv.js b/lib/mv.js
index 7e02b9a3..04cd4279 100755
--- a/lib/mv.js
+++ b/lib/mv.js
@@ -321,6 +321,12 @@ var mv = (function () {
       $("#frm-bl").append(html);
       $("#frm-bl-visible").append(html2);
       $(".bl." + classe + " input").bind("change", function (e) {
+        var checkbox = $(e.currentTarget);
+        var allChecked = $(".bl." + classe + " input:checked");
+        if (!checkbox.prop("checked") && allChecked.length === 0) {
+          checkbox.prop("checked", true);
+          return;
+        }
         var id = $(this).parent().parent().attr("data-layerid");
         var value = $(e.currentTarget).prop("checked");
         var select = $("#frm-bl-visible");