Tracking all of the issues brought up with the 08/24 accessibility pass on Contextual Menu control
Details on individual bugs can be found on SharePoint

• Bug 1 : [Accessibility][Forms and validation]: 'Actions' label is not associated with its corresponding control.
  • @KevinTCoughlin: This is a header node, so perhaps the correct fix here is to use aria-label on the search input as that element is missing a corresponding label.
• Bug 2 : [Accessibility][Screen reader]: Label or place holder is not provided for the Edit field(250) present under Contextual Menu with Sub Menus
• Bug 3 : [Accessibility][Screen reader]: Narrator focus moves twice on the first element of context menu in scan mode.
• Bug 4 : [Accessibility][Screen reader]: Name, Role and state is not properly defined for split buttons under 'ContextualMenu with checkable menu items and toggleable split button'.
• Bug 5 : [Accessibility][Screen reader]: Secondary text is not announced when user navigates in context menu under ContextualMenu with icons and secondary text [Fix ContextualMenuItemButton's secondary text never read by screen-reader #6670].
• Bug 6 : [Accessibility][Screen reader]: Narrator does not read notification alert properly.
• Bug 7 : [Accessibility][Screen reader]: In Scan mode user is not able to close the 'Contextual menu' using 'Esc key'.
  • @KevinTCoughlin: This is likely because scan focuses different elements and therefore the event isn't bubbling on the component.
• Bug 8 : [Accessibility][Keyboard Navigation]: Tab Focus is moving out of the Notification window which appears on activating 'Share w/split button'.
• Bug 9 : [Accessibility][Screen reader]: Narrator focus moves onto the separator line in scan mode. [ContextualMenu: Fix Narrator Separator Announcement #6876]
• Bug 10 : [Accessibility][Screen reader]: Narrator focus moves onto hidden elements in scan mode in backward navigation.
• Bug 11 : [Accessibility][Screen reader]: User is not able to access "Share w/split button " in scan mode.
• Bug 12 : [Accessibility][Programmatic access]: id attribute value must be unique.
• Bug 13 : [Accessibility][Programmatic access]: 'Hierarchy levels' are not defined for submenus.
• Bug 14 : [Functional]: Some controls are not implemented properly in 'Charm' submenu window.
• Bug 15 : [Accessibility][Usable]: Header/Label should be define for 'Categories group' in 'Categorize submenu'.
  • @KevinTCoughlin: Not sure if we can do this with current API. ariaLabel on subMenuProps adds the aria-label to the button, not the callout submenu.
• Bug 16 : [Accessibility][Programmatic access]: Role of the categories is not appropriate as multiple selection of categories could be possible.
• Bug 17 : [Accessibility][Usable]: Screen does not scroll down along with keyboard focus in back navigation.
• Bug 18 : [Accessibility][Keyboard]: User is not able to delete 'NAN' value from 'Hover delay' edit box under 'ContextualMenu with submenus' after entering invalid values.

Component: ContextualMenu

@micahgodbolt