diff --git a/app/assets/javascripts/my_modules.js b/app/assets/javascripts/my_modules.js
index de71ca6df..13cd2b826 100644
--- a/app/assets/javascripts/my_modules.js
+++ b/app/assets/javascripts/my_modules.js
@@ -108,6 +108,11 @@ function bindEditTagsAjax() {
   // tag.
   function initAddTagForm() {
     manageTagsModalBody.find('.add-tag-form')
+      .submit(function() {
+        var selectOptions = manageTagsModalBody.find('.add-tag-form .dropdown-menu li').length;
+        if (selectOptions === 0) return false;
+        return true;
+      })
       .on('ajax:success', function(e, data) {
         initTagsModalBody(data);
       });
diff --git a/app/assets/javascripts/projects/canvas.js.erb b/app/assets/javascripts/projects/canvas.js.erb
index eda3acb67..49d21437c 100644
--- a/app/assets/javascripts/projects/canvas.js.erb
+++ b/app/assets/javascripts/projects/canvas.js.erb
@@ -796,6 +796,11 @@ function bindEditTagsAjax(elements) {
   // tag.
   function initAddTagForm() {
     manageTagsModalBody.find(".add-tag-form")
+      .submit(function() {
+        var selectOptions = manageTagsModalBody.find('.add-tag-form .dropdown-menu li').length;
+        if (selectOptions === 0) return false;
+        return true;
+      })
       .on("ajax:success", function (e, data) {
         initTagsModalBody(data);
       });
diff --git a/app/controllers/my_module_tags_controller.rb b/app/controllers/my_module_tags_controller.rb
index 7dc692a82..2523bc1a9 100644
--- a/app/controllers/my_module_tags_controller.rb
+++ b/app/controllers/my_module_tags_controller.rb
@@ -55,7 +55,7 @@ class MyModuleTagsController < ApplicationController
   end
 
   def create
-    return render_403 unless mt_params[:tag_id]
+    return render_403 unless params[:my_module_tag] && mt_params[:tag_id]
 
     @mt = MyModuleTag.new(mt_params.merge(my_module: @my_module))
     @mt.created_by = current_user
@@ -125,6 +125,9 @@ class MyModuleTagsController < ApplicationController
 
   def destroy_by_tag_id
     tag = @my_module.my_module_tags.find_by_tag_id(params[:id])
+
+    return render_404 unless tag
+
     tag.destroy
     render json: { result: tag }
   end