FIX: Don't allow moving a category with children underneath another

category (creating grandchildren)

app/assets/javascripts/discourse/controllers/edit_category_controller.js

@@ -20,6 +20,11 @@ Discourse.EditCategoryController = Discourse.ObjectController.extend(Discourse.M
     });
   }.property(),
 
+  // We can change the parent if there are no children
+  subCategories: function() {
+    return Discourse.Category.list().filterBy('parent_category_id', this.get('id'));
+  }.property('model.id'),
+
   onShow: function() {
     this.changeSize();
     this.titleChanged();

app/assets/javascripts/discourse/helpers/application_helpers.js

@@ -73,6 +73,12 @@ Handlebars.registerHelper('categoryLinkRaw', function(property, options) {
   return categoryLinkHTML(property, options);
 });
 
+Handlebars.registerHelper('categoryBadge', function(property, options) {
+  var category = Em.Handlebars.get(this, property, options),
+      style = Discourse.HTML.categoryStyle(category);
+  return new Handlebars.SafeString("<span class='badge-category' style='" + style + "'>" + category.get('name') + "</span>");
+});
+
 /**
   Produces a bound link to a category
 

app/assets/javascripts/discourse/templates/modal/edit_category.js.handlebars

@@ -22,8 +22,15 @@
         </section>
 
         <section class='field'>
-          <label>{{i18n category.parent}}</label>
-          {{categoryChooser valueAttribute="id" value=parent_category_id categories=parentCategories}}
+          {{#if subCategories}}
+            <label>{{i18n categories.subcategories}}</label>
+            {{#each subCategories}}
+              {{categoryBadge this}}
+            {{/each}}
+          {{else}}
+            <label>{{i18n category.parent}}</label>
+            {{categoryChooser valueAttribute="id" value=parent_category_id categories=parentCategories}}
+          {{/if}}
         </section>
 
         {{#unless isUncategorized}}

config/locales/client.en.yml

@@ -196,7 +196,7 @@ en:
       latest: "Latest"
       latest_by: "latest by"
       toggle_ordering: "toggle ordering control"
-      subcategories: "Subcategories:"
+      subcategories: "Subcategories"
       topic_stats: "The number of new topics."
       topic_stat_sentence:
         one: "%{count} new topic in the past %{unit}."