diff --git a/accessible/base/NotificationController.cpp b/accessible/base/NotificationController.cpp
index 90722c63a4d7..b0794b3cbcc9 100644
--- a/accessible/base/NotificationController.cpp
+++ b/accessible/base/NotificationController.cpp
@@ -678,6 +678,8 @@ void NotificationController::WillRefresh(mozilla::TimeStamp aTime) {
                  "isn't created!");
   }
 
+  mDocument->ProcessPendingUpdates();
+
   nsTArray<CacheData> cache;
 
   // Process rendered text change notifications.
diff --git a/accessible/base/nsAccessibilityService.cpp b/accessible/base/nsAccessibilityService.cpp
index 53a3cfa723e2..3083edd2d002 100644
--- a/accessible/base/nsAccessibilityService.cpp
+++ b/accessible/base/nsAccessibilityService.cpp
@@ -484,6 +484,22 @@ void nsAccessibilityService::ContentRangeInserted(PresShell* aPresShell,
   }
 }
 
+void nsAccessibilityService::ScheduleAccessibilitySubtreeUpdate(
+    PresShell* aPresShell, nsIContent* aContent) {
+  DocAccessible* document = GetDocAccessible(aPresShell);
+#ifdef A11Y_LOG
+  if (logging::IsEnabled(logging::eTree)) {
+    logging::MsgBegin("TREE", "schedule update; doc: %p", document);
+    logging::Node("content node", aContent);
+    logging::MsgEnd();
+  }
+#endif
+
+  if (document) {
+    document->ScheduleTreeUpdate(aContent);
+  }
+}
+
 void nsAccessibilityService::ContentRemoved(PresShell* aPresShell,
                                             nsIContent* aChildNode) {
   DocAccessible* document = GetDocAccessible(aPresShell);
@@ -518,6 +534,27 @@ void nsAccessibilityService::TableLayoutGuessMaybeChanged(
   }
 }
 
+void nsAccessibilityService::ComboboxOptionMaybeChanged(
+    PresShell* aPresShell, nsIContent* aMutatingNode) {
+  DocAccessible* document = GetDocAccessible(aPresShell);
+  if (!document) {
+    return;
+  }
+
+  for (nsIContent* cur = aMutatingNode; cur; cur = cur->GetParent()) {
+    if (cur->IsHTMLElement(nsGkAtoms::option)) {
+      if (LocalAccessible* accessible = document->GetAccessible(cur)) {
+        document->FireDelayedEvent(nsIAccessibleEvent::EVENT_NAME_CHANGE,
+                                   accessible);
+        break;
+      }
+      if (cur->IsHTMLElement(nsGkAtoms::select)) {
+        break;
+      }
+    }
+  }
+}
+
 void nsAccessibilityService::UpdateText(PresShell* aPresShell,
                                         nsIContent* aContent) {
   DocAccessible* document = GetDocAccessible(aPresShell);
@@ -882,7 +919,7 @@ LocalAccessible* nsAccessibilityService::CreateAccessible(
   if (!frame || !frame->StyleVisibility()->IsVisible()) {
     // display:contents element doesn't have a frame, but retains the semantics.
     // All its children are unaffected.
-    if (nsCoreUtils::IsDisplayContents(content)) {
+    if (nsCoreUtils::CanCreateAccessibleWithoutFrame(content)) {
       const MarkupMapInfo* markupMap = GetMarkupMapInfoForNode(content);
       if (markupMap && markupMap->new_func) {
         RefPtr<LocalAccessible> newAcc =
diff --git a/accessible/base/nsAccessibilityService.h b/accessible/base/nsAccessibilityService.h
index 262b27d16f30..47a35ff70d4f 100644
--- a/accessible/base/nsAccessibilityService.h
+++ b/accessible/base/nsAccessibilityService.h
@@ -166,6 +166,14 @@ class nsAccessibilityService final : public mozilla::a11y::DocManager,
   void ContentRangeInserted(mozilla::PresShell* aPresShell,
                             nsIContent* aStartChild, nsIContent* aEndChild);
 
+  /**
+   * Triggers a re-evaluation of the a11y tree of aContent after the next
+   * refresh. This is important because whether we create accessibles may
+   * depend on the frame tree / style.
+   */
+  void ScheduleAccessibilitySubtreeUpdate(mozilla::PresShell* aPresShell,
+                                          nsIContent* aStartChild);
+
   /**
    * Notification used to update the accessible tree when content is removed.
    */
@@ -177,6 +185,12 @@ class nsAccessibilityService final : public mozilla::a11y::DocManager,
   void TableLayoutGuessMaybeChanged(mozilla::PresShell* aPresShell,
                                     nsIContent* aContent);
 
+  /**
+   * Notifies when a combobox <option> text or label changes.
+   */
+  void ComboboxOptionMaybeChanged(mozilla::PresShell*,
+                                  nsIContent* aMutatingNode);
+
   void UpdateText(mozilla::PresShell* aPresShell, nsIContent* aContent);
 
   /**
diff --git a/accessible/base/nsCoreUtils.cpp b/accessible/base/nsCoreUtils.cpp
index 325038c8287a..a2da8105bc8a 100644
--- a/accessible/base/nsCoreUtils.cpp
+++ b/accessible/base/nsCoreUtils.cpp
@@ -580,8 +580,26 @@ void nsCoreUtils::DispatchAccEvent(RefPtr<nsIAccessibleEvent> event) {
 }
 
 bool nsCoreUtils::IsDisplayContents(nsIContent* aContent) {
-  return aContent && aContent->IsElement() &&
-         aContent->AsElement()->IsDisplayContents();
+  auto* element = Element::FromNodeOrNull(aContent);
+  return element && element->IsDisplayContents();
+}
+
+bool nsCoreUtils::CanCreateAccessibleWithoutFrame(nsIContent* aContent) {
+  auto* element = Element::FromNodeOrNull(aContent);
+  if (!element) {
+    return false;
+  }
+  if (!element->HasServoData() || Servo_Element_IsDisplayNone(element)) {
+    // Out of the flat tree or in a display: none subtree.
+    return false;
+  }
+  if (element->IsDisplayContents()) {
+    return true;
+  }
+  // We don't have a frame, but we're not display: contents either.
+  // For now, only create accessibles for <option>/<optgroup> as our combobox
+  // select code depends on it.
+  return element->IsAnyOfHTMLElements(nsGkAtoms::option, nsGkAtoms::optgroup);
 }
 
 bool nsCoreUtils::IsDocumentVisibleConsideringInProcessAncestors(
diff --git a/accessible/base/nsCoreUtils.h b/accessible/base/nsCoreUtils.h
index 7c16c38ece4a..780078cbe645 100644
--- a/accessible/base/nsCoreUtils.h
+++ b/accessible/base/nsCoreUtils.h
@@ -318,6 +318,7 @@ class nsCoreUtils {
   static void DispatchAccEvent(RefPtr<nsIAccessibleEvent> aEvent);
 
   static bool IsDisplayContents(nsIContent* aContent);
+  static bool CanCreateAccessibleWithoutFrame(nsIContent* aContent);
 
   /**
    * Return whether the document and all its in-process ancestors are visible in
diff --git a/accessible/generic/DocAccessible.cpp b/accessible/generic/DocAccessible.cpp
index 64a881ffddcd..8505fea14563 100644
--- a/accessible/generic/DocAccessible.cpp
+++ b/accessible/generic/DocAccessible.cpp
@@ -131,6 +131,7 @@ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(DocAccessible,
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mAccessibleCache)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mAnchorJumpElm)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mInvalidationList)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mPendingUpdates)
   for (const auto& ar : tmp->mARIAOwnsHash.Values()) {
     for (uint32_t i = 0; i < ar->Length(); i++) {
       NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mARIAOwnsHash entry item");
@@ -148,6 +149,7 @@ NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN_INHERITED(DocAccessible, LocalAccessible)
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mAccessibleCache)
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mAnchorJumpElm)
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mInvalidationList)
+  NS_IMPL_CYCLE_COLLECTION_UNLINK(mPendingUpdates)
   NS_IMPL_CYCLE_COLLECTION_UNLINK_WEAK_REFERENCE
   tmp->mARIAOwnsHash.Clear();
 NS_IMPL_CYCLE_COLLECTION_UNLINK_END
@@ -457,6 +459,7 @@ void DocAccessible::Shutdown() {
 
   mAnchorJumpElm = nullptr;
   mInvalidationList.Clear();
+  mPendingUpdates.Clear();
 
   for (auto iter = mAccessibleCache.Iter(); !iter.Done(); iter.Next()) {
     LocalAccessible* accessible = iter.Data();
@@ -1164,6 +1167,25 @@ void DocAccessible::ContentInserted(nsIContent* aStartChildNode,
   mNotificationController->ScheduleContentInsertion(container, list);
 }
 
+void DocAccessible::ScheduleTreeUpdate(nsIContent* aContent) {
+  if (mPendingUpdates.Contains(aContent)) {
+    return;
+  }
+  mPendingUpdates.AppendElement(aContent);
+  mNotificationController->ScheduleProcessing();
+}
+
+void DocAccessible::ProcessPendingUpdates() {
+  auto updates = std::move(mPendingUpdates);
+  for (auto update : updates) {
+    if (update->GetComposedDoc() != mDocumentNode) {
+      continue;
+    }
+    // The pruning logic will take care of avoiding unnecessary notifications.
+    ContentInserted(update, update->GetNextSibling());
+  }
+}
+
 bool DocAccessible::PruneOrInsertSubtree(nsIContent* aRoot) {
   bool insert = false;
 
@@ -1178,7 +1200,7 @@ bool DocAccessible::PruneOrInsertSubtree(nsIContent* aRoot) {
     // then remove their accessibles and subtrees.
     while (nsIContent* childNode = iter.GetNextChild()) {
       if (!childNode->GetPrimaryFrame() &&
-          !nsCoreUtils::IsDisplayContents(childNode)) {
+          !nsCoreUtils::CanCreateAccessibleWithoutFrame(childNode)) {
         ContentRemoved(childNode);
       }
     }
@@ -1189,7 +1211,7 @@ bool DocAccessible::PruneOrInsertSubtree(nsIContent* aRoot) {
       for (nsIContent* childNode = aRoot->GetFirstChild(); childNode;
            childNode = childNode->GetNextSibling()) {
         if (!childNode->GetPrimaryFrame() &&
-            !nsCoreUtils::IsDisplayContents(childNode)) {
+            !nsCoreUtils::CanCreateAccessibleWithoutFrame(childNode)) {
           ContentRemoved(childNode);
         }
       }
@@ -1218,7 +1240,7 @@ bool DocAccessible::PruneOrInsertSubtree(nsIContent* aRoot) {
     // As well as removing the a11y subtree, we must also remove Accessibles
     // for DOM descendants, since some of these might be relocated Accessibles
     // and their DOM nodes are now hidden as well.
-    if (!frame && !nsCoreUtils::IsDisplayContents(aRoot)) {
+    if (!frame && !nsCoreUtils::CanCreateAccessibleWithoutFrame(aRoot)) {
       ContentRemoved(aRoot);
       return false;
     }
@@ -1280,7 +1302,8 @@ bool DocAccessible::PruneOrInsertSubtree(nsIContent* aRoot) {
   } else {
     // If there is no current accessible, and the node has a frame, or is
     // display:contents, schedule it for insertion.
-    if (aRoot->GetPrimaryFrame() || nsCoreUtils::IsDisplayContents(aRoot)) {
+    if (aRoot->GetPrimaryFrame() ||
+        nsCoreUtils::CanCreateAccessibleWithoutFrame(aRoot)) {
       // This may be a new subtree, the insertion process will recurse through
       // its descendants.
       if (!GetAccessibleOrDescendant(aRoot)) {
diff --git a/accessible/generic/DocAccessible.h b/accessible/generic/DocAccessible.h
index a792831628b1..f3b7e2748211 100644
--- a/accessible/generic/DocAccessible.h
+++ b/accessible/generic/DocAccessible.h
@@ -335,6 +335,11 @@ class DocAccessible : public HyperTextAccessibleWrap,
    */
   void ContentInserted(nsIContent* aStartChildNode, nsIContent* aEndChildNode);
 
+  /**
+   * @see nsAccessibilityService::ScheduleAccessibilitySubtreeUpdate
+   */
+  void ScheduleTreeUpdate(nsIContent* aContent);
+
   /**
    * Update the tree on content removal.
    */
@@ -490,6 +495,11 @@ class DocAccessible : public HyperTextAccessibleWrap,
    */
   void ProcessInvalidationList();
 
+  /**
+   * Process mPendingUpdates
+   */
+  void ProcessPendingUpdates();
+
   /**
    * Called from NotificationController to process this doc's
    * mMaybeBoundsChanged list. Sends a cache update for each acc in this
@@ -718,6 +728,11 @@ class DocAccessible : public HyperTextAccessibleWrap,
                    nsTArray<RefPtr<LocalAccessible>>>
       mARIAOwnsHash;
 
+  /**
+   * Keeps a list of pending subtrees to update post-refresh.
+   */
+  nsTArray<RefPtr<nsIContent>> mPendingUpdates;
+
   /**
    * Used to process notification from core and accessible events.
    */
diff --git a/accessible/html/HTMLSelectAccessible.cpp b/accessible/html/HTMLSelectAccessible.cpp
index 7c25f3c7b801..9e142f9959e0 100644
--- a/accessible/html/HTMLSelectAccessible.cpp
+++ b/accessible/html/HTMLSelectAccessible.cpp
@@ -16,6 +16,7 @@
 
 #include "nsCOMPtr.h"
 #include "mozilla/dom/HTMLOptionElement.h"
+#include "mozilla/dom/HTMLOptGroupElement.h"
 #include "mozilla/dom/HTMLSelectElement.h"
 #include "nsComboboxControlFrame.h"
 #include "nsContainerFrame.h"
@@ -121,22 +122,20 @@ role HTMLSelectOptionAccessible::NativeRole() const {
 }
 
 ENameValueFlag HTMLSelectOptionAccessible::NativeName(nsString& aName) const {
-  // CASE #1 -- great majority of the cases
-  // find the label attribute - this is what the W3C says we should use
-  mContent->AsElement()->GetAttr(kNameSpaceID_None, nsGkAtoms::label, aName);
-  if (!aName.IsEmpty()) return eNameOK;
-
-  // CASE #2 -- no label parameter, get the first child,
-  // use it if it is a text node
-  LocalAccessible* firstChild = LocalFirstChild();
-  nsIContent* text = firstChild ? firstChild->GetContent() : nullptr;
-  if (text && text->IsText()) {
-    nsTextEquivUtils::AppendTextEquivFromTextContent(text, &aName);
-    aName.CompressWhitespace();
+  if (auto* option = dom::HTMLOptionElement::FromNode(mContent)) {
+    option->GetAttr(nsGkAtoms::label, aName);
+    if (!aName.IsEmpty()) {
+      return eNameOK;
+    }
+    option->GetText(aName);
+    return eNameFromSubtree;
+  }
+  if (auto* group = dom::HTMLOptGroupElement::FromNode(mContent)) {
+    group->GetLabel(aName);
     return aName.IsEmpty() ? eNameOK : eNameFromSubtree;
   }
-
-  return eNameOK;
+  MOZ_ASSERT_UNREACHABLE("What content do we have?");
+  return eNameFromSubtree;
 }
 
 void HTMLSelectOptionAccessible::DOMAttributeChanged(
diff --git a/accessible/tests/browser/e10s/browser_treeupdate_optgroup.js b/accessible/tests/browser/e10s/browser_treeupdate_optgroup.js
index 15fed8112df9..55a9a26b6dcf 100644
--- a/accessible/tests/browser/e10s/browser_treeupdate_optgroup.js
+++ b/accessible/tests/browser/e10s/browser_treeupdate_optgroup.js
@@ -41,10 +41,7 @@ addAccessibleTask(
         {
           COMBOBOX_LIST: [
             {
-              GROUPING: [
-                { COMBOBOX_OPTION: [{ TEXT_LEAF: [] }] },
-                { COMBOBOX_OPTION: [{ TEXT_LEAF: [] }] },
-              ],
+              GROUPING: [{ COMBOBOX_OPTION: [] }, { COMBOBOX_OPTION: [] }],
             },
             {
               COMBOBOX_OPTION: [],
diff --git a/accessible/tests/browser/e10s/browser_treeupdate_select_dropdown.js b/accessible/tests/browser/e10s/browser_treeupdate_select_dropdown.js
index add454ceac49..caf07556479d 100644
--- a/accessible/tests/browser/e10s/browser_treeupdate_select_dropdown.js
+++ b/accessible/tests/browser/e10s/browser_treeupdate_select_dropdown.js
@@ -40,6 +40,7 @@ addAccessibleTask(
       const EventUtils = ContentTaskUtils.getEventUtils(content);
       EventUtils.synthesizeKey("VK_DOWN", { altKey: true }, content);
     });
+    info("Waiting for parent focus");
     let event = await focused;
     let dropdown = event.accessible.parent;
 
@@ -64,13 +65,8 @@ addAccessibleTask(
       "select",
       "select focused after collapsed"
     );
-    await invokeContentTask(browser, [], () => {
-      const { ContentTaskUtils } = ChromeUtils.import(
-        "resource://testing-common/ContentTaskUtils.jsm"
-      );
-      const EventUtils = ContentTaskUtils.getEventUtils(content);
-      EventUtils.synthesizeKey("VK_ESCAPE", {}, content);
-    });
+    EventUtils.synthesizeKey("VK_ESCAPE", {}, window);
+    info("Waiting for child focus");
     await focused;
   },
   { iframe: true, remoteIframe: true }
diff --git a/accessible/tests/mochitest/actions/test_select.html b/accessible/tests/mochitest/actions/test_select.html
index 3cc7c718495f..7f55dfc0efc3 100644
--- a/accessible/tests/mochitest/actions/test_select.html
+++ b/accessible/tests/mochitest/actions/test_select.html
@@ -32,42 +32,6 @@
             new focusChecker("lb_apple"),
           ],
         },
-        {
-          ID: "combobox",
-          actionIndex: 0,
-          actionName: "open",
-          events: CLICK_EVENTS,
-          eventSeq: [
-            new focusChecker("cb_orange"),
-          ],
-        },
-        {
-          ID: "cb_apple",
-          actionIndex: 0,
-          actionName: "select",
-          events: CLICK_EVENTS,
-          eventSeq: [
-            new focusChecker("combobox"),
-          ],
-        },
-        {
-          ID: "combobox",
-          actionIndex: 0,
-          actionName: "open",
-          events: CLICK_EVENTS,
-          eventSeq: [
-            new focusChecker("cb_apple"),
-          ],
-        },
-        {
-          ID: "combobox",
-          actionIndex: 0,
-          actionName: "close",
-          events: CLICK_EVENTS,
-          eventSeq: [
-            new focusChecker("combobox"),
-          ],
-        },
       ];
 
       testActions(actionsArray);
diff --git a/accessible/tests/mochitest/bounds/a11y.ini b/accessible/tests/mochitest/bounds/a11y.ini
index bdb8c02f90a2..e9f8a3d4eb35 100644
--- a/accessible/tests/mochitest/bounds/a11y.ini
+++ b/accessible/tests/mochitest/bounds/a11y.ini
@@ -3,4 +3,3 @@ support-files =
   !/accessible/tests/mochitest/*.js
 
 [test_list.html]
-[test_select.html]
diff --git a/accessible/tests/mochitest/bounds/test_select.html b/accessible/tests/mochitest/bounds/test_select.html
deleted file mode 100644
index ac9a501f32be..000000000000
--- a/accessible/tests/mochitest/bounds/test_select.html
+++ /dev/null
@@ -1,78 +0,0 @@
-<!DOCTYPE html>
-<html>
-<head>
-  <title>Accessible boundaries when page is zoomed</title>
-  <link rel="stylesheet" type="text/css"
-        href="chrome://mochikit/content/tests/SimpleTest/test.css" />
-
-  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
-  <script src="chrome://mochikit/content/tests/SimpleTest/EventUtils.js"></script>
-
-  <script type="application/javascript"
-          src="../common.js"></script>
-  <script type="application/javascript"
-          src="../role.js"></script>
-  <script type="application/javascript"
-          src="../layout.js"></script>
-  <script type="application/javascript"
-          src="../events.js"></script>
-
-  <script type="application/javascript">
-    function openComboboxNCheckBounds(aID) {
-      this.combobox = getAccessible(aID);
-      this.comboboxList = this.combobox.firstChild;
-      this.comboboxOption = this.comboboxList.firstChild;
-
-      this.eventSeq = [
-        new invokerChecker(EVENT_FOCUS, this.comboboxOption),
-      ];
-
-      this.invoke = function openComboboxNCheckBounds_invoke() {
-        getNode(aID).focus();
-        synthesizeKey("VK_DOWN", { altKey: true });
-      };
-
-      this.finalCheck = function openComboboxNCheckBounds_invoke() {
-        testBounds(this.comboboxOption);
-      };
-
-      this.getID = function openComboboxNCheckBounds_getID() {
-        return "open combobox and test boundaries";
-      };
-    }
-
-    // gA11yEventDumpToConsole = true;
-
-    var gQueue = null;
-
-    function doTest() {
-      // Combobox
-      testBounds("combobox");
-
-      // Option boundaries matches to combobox boundaries when collapsed.
-      var selectBounds = getBoundsForDOMElm("combobox");
-      testBounds("option1", selectBounds);
-
-      // Open combobox and test option boundaries.
-      gQueue = new eventQueue();
-      gQueue.push(new openComboboxNCheckBounds("combobox"));
-      gQueue.invoke(); // Will call SimpleTest.finish();
-    }
-
-    SimpleTest.waitForExplicitFinish();
-    addA11yLoadEvent(doTest);
-  </script>
-</head>
-<body>
-
-  <p id="display"></p>
-  <div id="content" style="display: none"></div>
-  <pre id="test">
-  </pre>
-
-  <select id="combobox">
-    <option id="option1">item1</option>
-    <option>item2</option>
-  </select>
-</body>
-</html>
diff --git a/accessible/tests/mochitest/events/test_focus_selects.html b/accessible/tests/mochitest/events/test_focus_selects.html
index e674110e67e2..ef5b598efe1e 100644
--- a/accessible/tests/mochitest/events/test_focus_selects.html
+++ b/accessible/tests/mochitest/events/test_focus_selects.html
@@ -100,26 +100,6 @@
       synthesizeKey("VK_DOWN");
       await p;
 
-      p = waitForEvent(EVENT_FOCUS, "cb_apple");
-      // current selected item is focused when combobox is expanded
-      synthesizeKey("VK_DOWN", { altKey: true });
-      await p;
-
-      p = waitForEvents({
-        expected: [
-          [EVENT_SELECTION, "cb_orange"],
-          stateChangeEventArgs("cb_orange", EXT_STATE_ACTIVE, true, true),
-        ],
-      });
-      // selected item is focused for expanded combobox
-      synthesizeKey("VK_UP");
-      await p;
-
-      p = waitForEvent(EVENT_FOCUS, "combobox");
-      // collapsed combobx keeps a focus
-      synthesizeKey("VK_ESCAPE");
-      await p;
-
       // no focus events for unfocused list controls when current item is
       // changed
 
@@ -141,14 +121,14 @@
 
       p = waitForEvents({
         expected: [
-          [EVENT_SELECTION, "cb_apple"],
-          stateChangeEventArgs("cb_apple", EXT_STATE_ACTIVE, true, true),
+          [EVENT_SELECTION, "cb_orange"],
+          stateChangeEventArgs("cb_orange", EXT_STATE_ACTIVE, true, true),
         ],
         unexpected: [[EVENT_FOCUS]],
       });
       // An unfocused selectable combobox gets selection change events,
       // and active state change events, but not focus.
-      getNode("cb_apple").selected = true;
+      getNode("cb_orange").selected = true;
       await p;
 
       SimpleTest.finish();
diff --git a/accessible/tests/mochitest/events/test_selection.html b/accessible/tests/mochitest/events/test_selection.html
index a976d54b30e6..a749dd9c4c9b 100644
--- a/accessible/tests/mochitest/events/test_selection.html
+++ b/accessible/tests/mochitest/events/test_selection.html
@@ -31,17 +31,11 @@
     function doTests() {
       gQueue = new eventQueue();
 
-      // open combobox
-      gQueue.push(new synthClick("combobox",
-                                 new invokerChecker(EVENT_FOCUS, "cb1_item1")));
-      gQueue.push(new synthDownKey("cb1_item1",
-                                   selChangeSeq("cb1_item1", "cb1_item2")));
 
       // closed combobox
-      gQueue.push(new synthEscapeKey("combobox",
-                                     new invokerChecker(EVENT_FOCUS, "combobox")));
-      gQueue.push(new synthDownKey("cb1_item2",
-                                   selChangeSeq("cb1_item2", "cb1_item3")));
+      gQueue.push(new synthFocus("combobox"));
+      gQueue.push(new synthDownKey("cb1_item1",
+                                   selChangeSeq("cb1_item1", "cb1_item2")));
 
       // listbox
       gQueue.push(new synthClick("lb1_item1",
diff --git a/accessible/tests/mochitest/states/test_selects.html b/accessible/tests/mochitest/states/test_selects.html
index 37ff56845825..c822fe376f4b 100644
--- a/accessible/tests/mochitest/states/test_selects.html
+++ b/accessible/tests/mochitest/states/test_selects.html
@@ -18,36 +18,9 @@
           src="../events.js"></script>
 
   <script type="application/javascript">
-    function openComboboxNCheckStates(aID) {
-      this.combobox = getAccessible(aID);
-      this.comboboxList = this.combobox.firstChild;
-      this.comboboxOption = this.comboboxList.firstChild;
-
-      this.eventSeq = [
-        new invokerChecker(EVENT_FOCUS, this.comboboxOption),
-      ];
-
-      this.invoke = function openComboboxNCheckStates_invoke() {
-        getNode(aID).focus();
-        synthesizeKey("VK_DOWN", { altKey: true });
-      };
-
-      this.finalCheck = function openComboboxNCheckStates_invoke() {
-        // Expanded state on combobox.
-        testStates(this.combobox, STATE_EXPANDED);
-
-        // Floating state on combobox list.
-        testStates(this.comboboxList, STATE_FLOATING);
-      };
-
-      this.getID = function openComboboxNCheckStates_getID() {
-        return "open combobox and test states";
-      };
-    }
 
     // gA11yEventDumpToConsole = true;
 
-    var gQueue = null;
     function doTest() {
       // combobox
       var combobox = getAccessible("combobox");
@@ -60,11 +33,11 @@
 
       var opt1 = comboboxList.firstChild;
       testStates(opt1, STATE_SELECTABLE | STATE_SELECTED | STATE_FOCUSABLE,
-                 EXT_STATE_ACTIVE, STATE_FOCUSED, 0);
+                 0, STATE_FOCUSED, 0);
 
       var opt2 = comboboxList.lastChild;
       testStates(opt2, STATE_SELECTABLE | STATE_FOCUSABLE, 0, STATE_SELECTED, 0,
-                 STATE_FOCUSED, EXT_STATE_ACTIVE);
+                 STATE_FOCUSED, 0);
 
       // collapsed combobox
       testStates("collapsedcombobox",
@@ -123,10 +96,7 @@
 //                 STATE_SELECTABLE | STATE_SELECTED | STATE_FOCUSABLE,
 //                 EXT_STATE_ACTIVE);
 
-      // open combobox
-      gQueue = new eventQueue();
-      gQueue.push(new openComboboxNCheckStates("combobox"));
-      gQueue.invoke(); // Will call */SimpleTest.finish();
+      SimpleTest.finish();
     }
 
     SimpleTest.waitForExplicitFinish();
diff --git a/accessible/tests/mochitest/tree/test_select.html b/accessible/tests/mochitest/tree/test_select.html
index 4f9fb35ecfb2..80c17b9ef437 100644
--- a/accessible/tests/mochitest/tree/test_select.html
+++ b/accessible/tests/mochitest/tree/test_select.html
@@ -64,34 +64,18 @@
                 role: ROLE_GROUPING,
                 children: [
                   {
-                    role: ROLE_STATICTEXT,
+                    role: ROLE_COMBOBOX_OPTION,
                     children: [ ],
                   },
                   {
                     role: ROLE_COMBOBOX_OPTION,
-                    children: [
-                      {
-                        role: ROLE_TEXT_LEAF,
-                      },
-                    ],
-                  },
-                  {
-                    role: ROLE_COMBOBOX_OPTION,
-                    children: [
-                      {
-                        role: ROLE_TEXT_LEAF,
-                      },
-                    ],
+                    children: [ ],
                   },
                 ],
               },
               {
                 role: ROLE_COMBOBOX_OPTION,
-                children: [
-                  {
-                    role: ROLE_TEXT_LEAF,
-                  },
-                ],
+                children: [ ],
               },
             ],
           },
diff --git a/accessible/tests/mochitest/treeupdate/test_optgroup.html b/accessible/tests/mochitest/treeupdate/test_optgroup.html
index 288de1dd1d96..943b73be4348 100644
--- a/accessible/tests/mochitest/treeupdate/test_optgroup.html
+++ b/accessible/tests/mochitest/treeupdate/test_optgroup.html
@@ -45,12 +45,8 @@
           { COMBOBOX: [
             { COMBOBOX_LIST: [
               { GROUPING: [
-                { COMBOBOX_OPTION: [
-                  { TEXT_LEAF: [] },
-                ] },
-                { COMBOBOX_OPTION: [
-                  { TEXT_LEAF: [] },
-                ] },
+                { COMBOBOX_OPTION: [ ] },
+                { COMBOBOX_OPTION: [ ] },
               ]},
               { COMBOBOX_OPTION: [] },
             ] },
diff --git a/accessible/tests/mochitest/treeupdate/test_select.html b/accessible/tests/mochitest/treeupdate/test_select.html
index 7ad532e18a41..eabb64f80fe7 100644
--- a/accessible/tests/mochitest/treeupdate/test_select.html
+++ b/accessible/tests/mochitest/treeupdate/test_select.html
@@ -39,12 +39,8 @@
         var tree =
           { COMBOBOX: [
             { COMBOBOX_LIST: [
-              { COMBOBOX_OPTION: [
-                { TEXT_LEAF: [] },
-              ] },
-              { COMBOBOX_OPTION: [
-                { TEXT_LEAF: [] },
-              ] },
+              { COMBOBOX_OPTION: [ ] },
+              { COMBOBOX_OPTION: [ ] },
             ] },
           ] };
         testAccessibleTree(this.select, tree);
diff --git a/dom/html/HTMLOptionElement.h b/dom/html/HTMLOptionElement.h
index 710ce2458176..251cbdabd17d 100644
--- a/dom/html/HTMLOptionElement.h
+++ b/dom/html/HTMLOptionElement.h
@@ -90,7 +90,7 @@ class HTMLOptionElement final : public nsGenericHTMLElement {
     }
   }
 
-  void GetLabel(DOMString& aLabel) {
+  void GetLabel(nsAString& aLabel) {
     if (!GetAttr(kNameSpaceID_None, nsGkAtoms::label, aLabel)) {
       GetText(aLabel);
     }
diff --git a/layout/forms/HTMLSelectEventListener.cpp b/layout/forms/HTMLSelectEventListener.cpp
index 158c390d0597..bc074dc1aa82 100644
--- a/layout/forms/HTMLSelectEventListener.cpp
+++ b/layout/forms/HTMLSelectEventListener.cpp
@@ -278,6 +278,16 @@ int32_t HTMLSelectEventListener::ItemsPerPage() const {
   return AssertedCast<int32_t>(size - 1u);
 }
 
+void HTMLSelectEventListener::OptionValueMightHaveChanged(
+    nsIContent* aMutatingNode) {
+#ifdef ACCESSIBILITY
+  if (nsAccessibilityService* acc = PresShell::GetAccessibilityService()) {
+    acc->ComboboxOptionMaybeChanged(mElement->OwnerDoc()->GetPresShell(),
+                                    aMutatingNode);
+  }
+#endif
+}
+
 void HTMLSelectEventListener::AttributeChanged(dom::Element* aElement,
                                                int32_t aNameSpaceID,
                                                nsAtom* aAttribute,
@@ -285,6 +295,8 @@ void HTMLSelectEventListener::AttributeChanged(dom::Element* aElement,
                                                const nsAttrValue* aOldValue) {
   if (aElement->IsHTMLElement(nsGkAtoms::option) &&
       aNameSpaceID == kNameSpaceID_None && aAttribute == nsGkAtoms::label) {
+    // A11y has its own mutation listener for this so no need to do
+    // OptionValueMightHaveChanged().
     ComboboxMightHaveChanged();
   }
 }
@@ -292,6 +304,7 @@ void HTMLSelectEventListener::AttributeChanged(dom::Element* aElement,
 void HTMLSelectEventListener::CharacterDataChanged(
     nsIContent* aContent, const CharacterDataChangeInfo&) {
   if (nsContentUtils::IsInSameAnonymousTree(mElement, aContent)) {
+    OptionValueMightHaveChanged(aContent);
     ComboboxMightHaveChanged();
   }
 }
@@ -299,28 +312,36 @@ void HTMLSelectEventListener::CharacterDataChanged(
 void HTMLSelectEventListener::ContentRemoved(nsIContent* aChild,
                                              nsIContent* aPreviousSibling) {
   if (nsContentUtils::IsInSameAnonymousTree(mElement, aChild)) {
+    OptionValueMightHaveChanged(aChild);
     ComboboxMightHaveChanged();
   }
 }
 
 void HTMLSelectEventListener::ContentAppended(nsIContent* aFirstNewContent) {
   if (nsContentUtils::IsInSameAnonymousTree(mElement, aFirstNewContent)) {
+    OptionValueMightHaveChanged(aFirstNewContent);
     ComboboxMightHaveChanged();
   }
 }
 
 void HTMLSelectEventListener::ContentInserted(nsIContent* aChild) {
   if (nsContentUtils::IsInSameAnonymousTree(mElement, aChild)) {
+    OptionValueMightHaveChanged(aChild);
     ComboboxMightHaveChanged();
   }
 }
 
 void HTMLSelectEventListener::ComboboxMightHaveChanged() {
   if (nsIFrame* f = mElement->GetPrimaryFrame()) {
+    PresShell* ps = f->PresShell();
     // nsComoboxControlFrame::Reflow updates the selected text. AddOption /
     // RemoveOption / etc takes care of keeping the displayed index up to date.
-    f->PresShell()->FrameNeedsReflow(f, IntrinsicDirty::StyleChange,
-                                     NS_FRAME_IS_DIRTY);
+    ps->FrameNeedsReflow(f, IntrinsicDirty::StyleChange, NS_FRAME_IS_DIRTY);
+#ifdef ACCESSIBILITY
+    if (nsAccessibilityService* acc = PresShell::GetAccessibilityService()) {
+      acc->ScheduleAccessibilitySubtreeUpdate(ps, mElement);
+    }
+#endif
   }
 }
 
diff --git a/layout/forms/HTMLSelectEventListener.h b/layout/forms/HTMLSelectEventListener.h
index 220b37fa69d5..452610a2175c 100644
--- a/layout/forms/HTMLSelectEventListener.h
+++ b/layout/forms/HTMLSelectEventListener.h
@@ -88,6 +88,7 @@ class HTMLSelectEventListener final : public nsStubMutationObserver,
       int32_t aFromIndex, int32_t* aFoundIndex = nullptr) const;
 
   void ComboboxMightHaveChanged();
+  void OptionValueMightHaveChanged(nsIContent* aMutatingNode);
 
   ~HTMLSelectEventListener();