Always show article category headers (do not unlist them on list.js search)

app/assets/javascripts/list.unlist.js

@@ -136,9 +136,9 @@ List.prototype.templateEngines.unlist = function(list, settings) {
         $(item.elm).removeClass('unlisted');
     };
     this.hide = function(item) {
-        if (item.elm !== undefined) {
-            $(item.elm).addClass('unlisted');
-        }
+        ensure.created(item);
+        $(item.elm).addClass('unlisted');
+        listSource.appendChild(item.elm);
     };
     this.clear = function() {
         $(listSource.childNodes).addClass('unlisted');

app/assets/stylesheets/list.unlist.css

@@ -1,3 +1,3 @@
-.list .unlisted {
+.list .unlisted:not(.no-unlist) {
 	display: none;
 }

app/views/group_orders/_form.html.haml

@@ -67,8 +67,8 @@
         %th{style: "width:15px;"}= t '.sum'
     %tbody.list
       - @order.articles_grouped_by_category.each do |category, order_articles|
-        %tr.article-category
-          %td.name
+        %tr.no-unlist.article-category
+          %td
             = category
             %i.icon-tag
           %td{colspan: "9"}