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diff --git a/accessible/mac/mozSelectableElements.mm b/accessible/mac/mozSelectableElements.mm
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+/* clang-format off */
+/* -*- Mode: Objective-C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* clang-format on */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#import "mozSelectableElements.h"
+#import "MOXWebAreaAccessible.h"
+#import "MacUtils.h"
+#include "LocalAccessible-inl.h"
+#include "nsCocoaUtils.h"
+
+using namespace mozilla::a11y;
+
+@implementation mozSelectableAccessible
+
+/**
+ * Return the mozAccessibles that are selectable.
+ */
+- (NSArray*)selectableChildren {
+  NSArray* toFilter;
+  if ([self isKindOfClass:[mozMenuAccessible class]]) {
+    // If we are a menu, our children are only selectable if they are visible
+    // so we filter this array instead of our unignored children list, which may
+    // contain invisible items.
+    toFilter = [static_cast<mozMenuAccessible*>(self) moxVisibleChildren];
+  } else {
+    toFilter = [self moxUnignoredChildren];
+  }
+  return [toFilter
+      filteredArrayUsingPredicate:[NSPredicate predicateWithBlock:^BOOL(
+                                                   mozAccessible* child,
+                                                   NSDictionary* bindings) {
+        return [child isKindOfClass:[mozSelectableChildAccessible class]];
+      }]];
+}
+
+- (void)moxSetSelectedChildren:(NSArray*)selectedChildren {
+  for (id child in [self selectableChildren]) {
+    BOOL selected =
+        [selectedChildren indexOfObjectIdenticalTo:child] != NSNotFound;
+    [child moxSetSelected:@(selected)];
+  }
+}
+
+/**
+ * Return the mozAccessibles that are actually selected.
+ */
+- (NSArray*)moxSelectedChildren {
+  return [[self selectableChildren]
+      filteredArrayUsingPredicate:[NSPredicate predicateWithBlock:^BOOL(
+                                                   mozAccessible* child,
+                                                   NSDictionary* bindings) {
+        // Return mozSelectableChildAccessibles that have are selected (truthy
+        // value).
+        return [[(mozSelectableChildAccessible*)child moxSelected] boolValue];
+      }]];
+}
+
+@end
+
+@implementation mozSelectableChildAccessible
+
+- (NSNumber*)moxSelected {
+  return @([self stateWithMask:states::SELECTED] != 0);
+}
+
+- (void)moxSetSelected:(NSNumber*)selected {
+  // Get SELECTABLE and UNAVAILABLE state.
+  uint64_t state =
+      [self stateWithMask:(states::SELECTABLE | states::UNAVAILABLE)];
+  if ((state & states::SELECTABLE) == 0 || (state & states::UNAVAILABLE) != 0) {
+    // The object is either not selectable or is unavailable. Don't do anything.
+    return;
+  }
+
+  mGeckoAccessible->SetSelected([selected boolValue]);
+
+  // We need to invalidate the state because the accessibility service
+  // may check the selected attribute synchornously and not wait for
+  // selection events.
+  [self invalidateState];
+}
+
+@end
+
+@implementation mozTabGroupAccessible
+
+- (NSArray*)moxTabs {
+  return [self selectableChildren];
+}
+
+- (NSArray*)moxContents {
+  return [self moxUnignoredChildren];
+}
+
+- (id)moxValue {
+  // The value of a tab group is its selected child. In the case
+  // of multiple selections this will return the first one.
+  return [[self moxSelectedChildren] firstObject];
+}
+
+@end
+
+@implementation mozTabAccessible
+
+- (NSString*)moxRoleDescription {
+  return utils::LocalizedString(u"tab"_ns);
+}
+
+- (id)moxValue {
+  // Retuens 1 if item is selected, 0 if not.
+  return [self moxSelected];
+}
+
+@end
+
+@implementation mozListboxAccessible
+
+- (BOOL)moxIgnoreChild:(mozAccessible*)child {
+  if (!child || child->mRole == roles::GROUPING) {
+    return YES;
+  }
+
+  return [super moxIgnoreChild:child];
+}
+
+- (BOOL)disableChild:(mozAccessible*)child {
+  return ![child isKindOfClass:[mozSelectableChildAccessible class]];
+}
+
+- (NSString*)moxOrientation {
+  return NSAccessibilityUnknownOrientationValue;
+}
+
+@end
+
+@implementation mozOptionAccessible
+
+- (NSString*)moxTitle {
+  return @"";
+}
+
+- (id)moxValue {
+  // Swap title and value of option so it behaves more like a AXStaticText.
+  return [super moxTitle];
+}
+
+@end
+
+@implementation mozMenuAccessible
+
+- (NSString*)moxTitle {
+  return @"";
+}
+
+- (NSString*)moxLabel {
+  return @"";
+}
+
+- (BOOL)moxIgnoreWithParent:(mozAccessible*)parent {
+  // This helps us generate the correct moxChildren array for
+  // a sub menu -- that returned array should contain all
+  // menu items, regardless of if they are visible or not.
+  // Because moxChildren does ignore filtering, and because
+  // our base ignore method filters out invisible accessibles,
+  // we override this method.
+  if ([parent isKindOfClass:[MOXWebAreaAccessible class]] ||
+      [parent isKindOfClass:[MOXRootGroup class]]) {
+    // We are a top level menu. Check our visibility the normal way
+    return [super moxIgnoreWithParent:parent];
+  }
+
+  if ([parent isKindOfClass:[mozMenuItemAccessible class]] &&
+      [parent geckoAccessible]->Role() == roles::PARENT_MENUITEM) {
+    // We are a submenu. If our parent menu item is in an open menu
+    // we should not be ignored
+    id grandparent = [parent moxParent];
+    if ([grandparent isKindOfClass:[mozMenuAccessible class]]) {
+      mozMenuAccessible* parentMenu =
+          static_cast<mozMenuAccessible*>(grandparent);
+      return ![parentMenu isOpened];
+    }
+  }
+
+  // Otherwise, we call into our superclass's ignore method
+  // to handle menus that are not submenus
+  return [super moxIgnoreWithParent:parent];
+}
+
+- (NSArray*)moxVisibleChildren {
+  // VO expects us to expose two lists of children on menus: all children
+  // (done in moxUnignoredChildren), and children which are visible (here).
+  // We implement ignoreWithParent for both menus and menu items
+  // to ensure moxUnignoredChildren returns a complete list of children
+  // regardless of visibility, see comments in those methods for additional
+  // info.
+  return [[self moxChildren]
+      filteredArrayUsingPredicate:[NSPredicate predicateWithBlock:^BOOL(
+                                                   mozAccessible* child,
+                                                   NSDictionary* bindings) {
+        if (LocalAccessible* acc = [child geckoAccessible]->AsLocal()) {
+          if (acc->IsContent() && acc->GetContent()->IsXULElement()) {
+            return ((acc->VisibilityState() & states::INVISIBLE) == 0);
+          }
+        }
+        return true;
+      }]];
+}
+
+- (id)moxTitleUIElement {
+  id parent = [self moxUnignoredParent];
+  if (parent && [parent isKindOfClass:[mozAccessible class]]) {
+    return parent;
+  }
+
+  return nil;
+}
+
+- (void)moxPostNotification:(NSString*)notification {
+  if ([notification isEqualToString:@"AXMenuOpened"]) {
+    mIsOpened = YES;
+  } else if ([notification isEqualToString:@"AXMenuClosed"]) {
+    mIsOpened = NO;
+  }
+
+  [super moxPostNotification:notification];
+}
+
+- (void)expire {
+  if (mIsOpened) {
+    // VO needs to receive a menu closed event when the menu goes away.
+    // If the menu is being destroyed, send a menu closed event first.
+    [self moxPostNotification:@"AXMenuClosed"];
+  }
+
+  [super expire];
+}
+
+- (BOOL)isOpened {
+  return mIsOpened;
+}
+
+@end
+
+@implementation mozMenuItemAccessible
+
+- (NSString*)moxLabel {
+  return @"";
+}
+
+- (BOOL)moxIgnoreWithParent:(mozAccessible*)parent {
+  // This helps us generate the correct moxChildren array for
+  // a mozMenuAccessible; the returned array should contain all
+  // menu items, regardless of if they are visible or not.
+  // Because moxChildren does ignore filtering, and because
+  // our base ignore method filters out invisible accessibles,
+  // we override this method.
+  Accessible* parentAcc = [parent geckoAccessible];
+  if (parentAcc) {
+    Accessible* grandparentAcc = parentAcc->Parent();
+    if (mozAccessible* directGrandparent =
+            GetNativeFromGeckoAccessible(grandparentAcc)) {
+      if ([directGrandparent isKindOfClass:[MOXWebAreaAccessible class]]) {
+        return [parent moxIgnoreWithParent:directGrandparent];
+      }
+    }
+  }
+
+  id grandparent = [parent moxParent];
+  if ([grandparent isKindOfClass:[mozMenuItemAccessible class]]) {
+    mozMenuItemAccessible* acc =
+        static_cast<mozMenuItemAccessible*>(grandparent);
+    if ([acc geckoAccessible]->Role() == roles::PARENT_MENUITEM) {
+      mozMenuAccessible* parentMenu = static_cast<mozMenuAccessible*>(parent);
+      // if we are a menu item in a submenu, display only when
+      // parent menu item is open
+      return ![parentMenu isOpened];
+    }
+  }
+
+  // Otherwise, we call into our superclass's method to handle
+  // menuitems that are not within submenus
+  return [super moxIgnoreWithParent:parent];
+}
+
+- (NSString*)moxMenuItemMarkChar {
+  LocalAccessible* acc = mGeckoAccessible->AsLocal();
+  if (acc && acc->IsContent() &&
+      acc->GetContent()->IsXULElement(nsGkAtoms::menuitem)) {
+    // We need to provide a marker character. This is the visible "√" you see
+    // on dropdown menus. In our a11y tree this is a single child text node
+    // of the menu item.
+    // We do this only with XUL menuitems that conform to the native theme, and
+    // not with aria menu items that might have a pseudo element or something.
+    if (acc->ChildCount() == 1 &&
+        acc->LocalFirstChild()->Role() == roles::STATICTEXT) {
+      nsAutoString marker;
+      acc->LocalFirstChild()->Name(marker);
+      if (marker.Length() == 1) {
+        return nsCocoaUtils::ToNSString(marker);
+      }
+    }
+  }
+
+  return nil;
+}
+
+- (NSNumber*)moxSelected {
+  // Our focused state is equivelent to native selected states for menus.
+  return @([self stateWithMask:states::FOCUSED] != 0);
+}
+
+- (void)handleAccessibleEvent:(uint32_t)eventType {
+  switch (eventType) {
+    case nsIAccessibleEvent::EVENT_FOCUS:
+      [self invalidateState];
+      // Our focused state is equivelent to native selected states for menus.
+      mozAccessible* parent = (mozAccessible*)[self moxUnignoredParent];
+      [parent moxPostNotification:
+                  NSAccessibilitySelectedChildrenChangedNotification];
+      break;
+  }
+
+  [super handleAccessibleEvent:eventType];
+}
+
+- (void)moxPerformPress {
+  [super moxPerformPress];
+  // when a menu item is pressed (chosen), we need to tell
+  // VoiceOver about it, so we send this notification
+  [self moxPostNotification:@"AXMenuItemSelected"];
+}
+
+@end