diff --git a/app/controllers/knowledge_explorer/knowledge_explorer_controller.rb b/app/controllers/knowledge_explorer/knowledge_explorer_controller.rb
index 97033d0..a615cb8 100644
--- a/app/controllers/knowledge_explorer/knowledge_explorer_controller.rb
+++ b/app/controllers/knowledge_explorer/knowledge_explorer_controller.rb
@@ -52,7 +52,7 @@ module KnowledgeExplorer
       category_topic_lists = []
 
       categories.each do |c|
-        if topic_list = TopicQuery.new(current_user, category: c.id).list_latest
+        if topic_list = TopicQuery.new(current_user, category: c.id, no_subcategories: true).list_latest
           category_topic_lists << TopicListSerializer.new(topic_list, scope: @guardian).as_json
         end
       end
@@ -98,7 +98,7 @@ module KnowledgeExplorer
     def knowledge_explorer_categories
       selected_categories = SiteSetting.knowledge_explorer_categories.split("|")
 
-      categories = Category.where('slug IN (?)', selected_categories)
+      categories = Category.where('id IN (?)', selected_categories)
 
       categories.select { |c| @guardian.can_see_category?(c) }
     end
diff --git a/config/settings.yml b/config/settings.yml
index 58b3534..53fb679 100644
--- a/config/settings.yml
+++ b/config/settings.yml
@@ -3,7 +3,7 @@ plugins:
     default: false
     client: true
   knowledge_explorer_categories:
-    type: list
+    type: category_list
     default: ""
     client: true
   knowledge_explorer_tags:
diff --git a/plugin.rb b/plugin.rb
index 27b1fc1..3b35fc0 100644
--- a/plugin.rb
+++ b/plugin.rb
@@ -16,7 +16,7 @@ after_initialize do
     if Search.respond_to? :advanced_filter
       Search.advanced_filter(/in:kb/) do |posts|
         selected_categories = SiteSetting.knowledge_explorer_categories.split("|")
-        categories = Category.where('slug IN (?)', selected_categories).pluck(:id)
+        categories = Category.where('id IN (?)', selected_categories).pluck(:id)
 
         selected_tags = SiteSetting.knowledge_explorer_tags.split("|")
         tags = Tag.where('name IN (?)', selected_tags).pluck(:id)