diff --git a/media/js/zamboni/devhub.js b/media/js/zamboni/devhub.js
index 3588381fb4..26be49ab2b 100644
--- a/media/js/zamboni/devhub.js
+++ b/media/js/zamboni/devhub.js
@@ -909,16 +909,21 @@ function initCatFields() {
             $main = $(this).find(".addon-categories"),
             $misc = $(this).find(".addon-misc-category"),
             maxCats = parseInt($parent.attr("data-max-categories"));
-        var checkMain = function() {
+        var checkMainDefault = function() {
             var checkedLength = $("input:checked", $main).length,
                 disabled = checkedLength >= maxCats;
-            $("input", $misc).attr("checked", checkedLength <= 0);
             $("input:not(:checked)", $main).attr("disabled", disabled);
+            return checkedLength;
+        };
+        var checkMain = function() {
+            var checkedLength = checkMainDefault();
+            $("input", $misc).attr("checked", checkedLength <= 0);
         };
         var checkOther = function() {
             $("input", $main).attr("checked", false).attr("disabled", false);
         };
-        $("input", $main).live("change", checkMain).trigger("change");
+        checkMainDefault();
+        $("input", $main).live("change", checkMain);
         $("input", $misc).live("change", checkOther);
     });
 }
diff --git a/media/js/zamboni/tests/devhub_tests.js b/media/js/zamboni/tests/devhub_tests.js
index 7871477d45..5cb9c1ea92 100644
--- a/media/js/zamboni/tests/devhub_tests.js
+++ b/media/js/zamboni/tests/devhub_tests.js
@@ -1,5 +1,37 @@
 $(document).ready(function(){
 
+var catFixture = {
+    setup: function() {
+        this.sandbox = tests.createSandbox('#addon-cats');
+        initCatFields();
+    },
+    teardown: function() {
+        this.sandbox.remove();
+    }
+};
+
+module('initCatFields', catFixture);
+
+test('Default with initial categories', function() {
+    var scope = $("#addon-cats-fx", self.sandbox);
+    var checkedChoices = $("input:checked", scope);
+    equals(checkedChoices.length, 2);
+    equals(checkedChoices[0].id, "id_form-0-categories_1");
+    equals(checkedChoices[1].id, "id_form-0-categories_2");
+
+    // 2 categories are selected, the other category should be disabled.
+    var max = scope.parent("div").attr("data-max-categories");
+    equals(parseInt(max), 2);
+    var disabledChoices = $("input:disabled", scope);
+    equals(disabledChoices.length, 1);
+    equals(disabledChoices[0].id, "id_form-0-categories_0");
+});
+
+test('Default without initial categories', function() {
+    equals($("#addon-cats-tb input:checked", self.sandbox).length, 0);
+});
+
+
 function pushTiersAndResults($suite, tiers, results) {
     $.each(['1','2','3','4'], function(i, val) {
         tiers.push($('[class~="test-tier"][data-tier="' + val + '"]',
diff --git a/templates/qunit.html b/templates/qunit.html
index 22c8fc59a3..194d479b07 100644
--- a/templates/qunit.html
+++ b/templates/qunit.html
@@ -117,6 +117,32 @@
       <a id="edit_slug" href="#">{{ _('Edit') }}</a>
     </span>
   </div>
+  <div id="addon-cats" data-max-categories="2">
+    <div data-max-categories="2">
+      <div id="addon-cats-fx" class="select-addon-cats">
+        <label>Select <b>up to 2</b> Firefox categories for this add-on:</label>
+        <ul class="addon-categories">
+          <li><label for="id_form-0-categories_0"><input type="checkbox" name="form-0-categories" value="72" id="id_form-0-categories_0" /> Alerts &amp; Updates</label></li>
+          <li><label for="id_form-0-categories_1"><input checked="checked" type="checkbox" name="form-0-categories" value="14" id="id_form-0-categories_1" /> Appearance</label></li>
+          <li><label for="id_form-0-categories_2"><input checked="checked" type="checkbox" name="form-0-categories" value="22" id="id_form-0-categories_2" /> Bookmarks</label></li>
+        </ul>
+        <ul class="addon-misc-category">
+          <li><label for="id_form-0-categories_13"><input type="checkbox" name="form-0-categories" value="73" id="id_form-0-categories_13" /> My add-on doesn&#39;t fit into any of the categories</label></li>
+        </ul>
+      </div>
+      <div id="addon-cats-tb" class="select-addon-cats">
+        <label>Select <b>up to 2</b> Thunderbird categories for this add-on:</label>
+        <ul class="addon-categories">
+          <li><label for="id_form-1-categories_0"><input type="checkbox" name="form-1-categories" value="23" id="id_form-1-categories_0" /> Contacts</label></li>
+          <li><label for="id_form-1-categories_1"><input type="checkbox" name="form-1-categories" value="69" id="id_form-1-categories_1" /> Language Support</label></li>
+        </ul>
+        <ul class="addon-misc-category">
+          <li><label for="id_form-1-categories_4"><input type="checkbox" name="form-1-categories" value="50" id="id_form-1-categories_4" /> My add-on doesn&#39;t fit into any of the categories</label></li>
+        </ul>
+      </div>
+    </div>
+  </div>
+
 
   <script src="{{ url('jsi18n') }}/build:{{ BUILD_ID_JS }}"></script>
   {{ js('common') }}