diff --git a/accessible/generic/Accessible.cpp b/accessible/generic/Accessible.cpp
index a3e72048af2..fce078d694c 100644
--- a/accessible/generic/Accessible.cpp
+++ b/accessible/generic/Accessible.cpp
@@ -1238,11 +1238,13 @@ Accessible::ApplyARIAState(uint64_t* aState) const
       *aState &= ~states::READONLY;
 
     if (mContent->HasID()) {
-      // If has a role & ID and aria-activedescendant on the container, assume focusable
-      nsIContent *ancestorContent = mContent;
-      while ((ancestorContent = ancestorContent->GetParent()) != nullptr) {
-        if (ancestorContent->HasAttr(kNameSpaceID_None, nsGkAtoms::aria_activedescendant)) {
-            // ancestor has activedescendant property, this content could be active
+      // If has a role & ID and aria-activedescendant on the container, assume
+      // focusable.
+      const Accessible* ancestor = this;
+      while ((ancestor = ancestor->Parent()) && !ancestor->IsDoc()) {
+        dom::Element* el = ancestor->Elm();
+        if (el &&
+            el->HasAttr(kNameSpaceID_None, nsGkAtoms::aria_activedescendant)) {
           *aState |= states::FOCUSABLE;
           break;
         }
@@ -1251,12 +1253,12 @@ Accessible::ApplyARIAState(uint64_t* aState) const
   }
 
   if (*aState & states::FOCUSABLE) {
-    // Special case: aria-disabled propagates from ancestors down to any focusable descendant
-    nsIContent *ancestorContent = mContent;
-    while ((ancestorContent = ancestorContent->GetParent()) != nullptr) {
-      if (ancestorContent->AttrValueIs(kNameSpaceID_None, nsGkAtoms::aria_disabled,
-                                       nsGkAtoms::_true, eCaseMatters)) {
-          // ancestor has aria-disabled property, this is disabled
+    // Propogate aria-disabled from ancestors down to any focusable descendant.
+    const Accessible* ancestor = this;
+    while ((ancestor = ancestor->Parent()) && !ancestor->IsDoc()) {
+      dom::Element* el = ancestor->Elm();
+      if (el && el->AttrValueIs(kNameSpaceID_None, nsGkAtoms::aria_disabled,
+                                nsGkAtoms::_true, eCaseMatters)) {
         *aState |= states::UNAVAILABLE;
         break;
       }
diff --git a/accessible/tests/mochitest/events/test_focus_aria_activedescendant.html b/accessible/tests/mochitest/events/test_focus_aria_activedescendant.html
index 4c2a2a29624..4cd57fe3b38 100644
--- a/accessible/tests/mochitest/events/test_focus_aria_activedescendant.html
+++ b/accessible/tests/mochitest/events/test_focus_aria_activedescendant.html
@@ -51,7 +51,7 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=429547
         var container  = getNode(aID);
         var itemNode = document.createElement("div");
         itemNode.setAttribute("id", aNewItemID);
-        itemNode.textContent = "item3";
+        itemNode.textContent = aNewItemID;
         container.appendChild(itemNode);
 
         container.setAttribute("aria-activedescendant", aNewItemID);
@@ -68,14 +68,15 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=429547
     {
       gQueue = new eventQueue();
 
-      gQueue.push(new synthFocus("container", new focusChecker("item1")));
-      gQueue.push(new changeARIAActiveDescendant("container", "item2"));
+      gQueue.push(new synthFocus("listbox", new focusChecker("item1")));
+      gQueue.push(new changeARIAActiveDescendant("listbox", "item2"));
+      gQueue.push(new changeARIAActiveDescendant("listbox", "item3"));
 
       gQueue.push(new synthFocus("combobox_entry", new focusChecker("combobox_entry")));
       gQueue.push(new changeARIAActiveDescendant("combobox", "combobox_option2"));
 
       todo(false, "No focus for inserted element, bug 687011");
-      //gQueue.push(new insertItemNFocus("container", "item3"));
+      //gQueue.push(new insertItemNFocus("listbox", "item4"));
 
       gQueue.invoke(); // Will call SimpleTest.finish();
     }
@@ -101,10 +102,12 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=429547
   <pre id="test">
   </pre>
 
-  <div role="listbox" aria-activedescendant="item1" id="container" tabindex="1">
+  <div role="listbox" aria-activedescendant="item1" id="listbox" tabindex="1"
+       aria-owns="item3">
     <div role="listitem" id="item1">item1</div>
     <div role="listitem" id="item2">item2</div>
   </div>
+  <div role="listitem" id="item3">item3</div>
 
   <div role="combobox" id="combobox">
     <input id="combobox_entry">
diff --git a/accessible/tests/mochitest/states/test_aria.html b/accessible/tests/mochitest/states/test_aria.html
index d0f268fca29..7d1ecf65083 100644
--- a/accessible/tests/mochitest/states/test_aria.html
+++ b/accessible/tests/mochitest/states/test_aria.html
@@ -500,7 +500,8 @@
   <!-- Test that aria-disabled state gets propagated to all descendants -->
   <div id="group" role="group" aria-disabled="true">
     <button>hi</button>
-    <div tabindex="0" role="listbox" aria-activedescendant="item1">
+    <div tabindex="0" role="listbox" aria-activedescendant="item1"
+         aria-owns="item5">
       <div role="option" id="item1">Item 1</div>
       <div role="option" id="item2">Item 2</div>
       <div role="option" id="item3">Item 3</div>
@@ -508,6 +509,7 @@
     </div>
     <div role="slider" tabindex="0">A slider</div>
   </div>
+  <div role="option" id="item5">Item 5</div>
 
   <!-- Test active state -->
   <div id="as_listbox" tabindex="0" role="listbox"