A11y_AzureNotebooks_Jupyter_MenuBar_Keyboard: Keyboard focus goes outside the "File" menuitem instead of remaining inside,while navigating inside "File" menuitem.

[AccessibilityTestingTeam-TCS]

EnvironmentDetails:
Application Name:AzureNotebooks_Jyupter
Login Url: notebooks.azure.com
BrowserDetails:
Edge:Microsoft Edge 41.16299.611.0
Operating System:Windows10

ReproSteps:

1. Login with the appropriate credentials to azure notebook account.
2. Navigate to any of the file names present in the samples-->>clickin the file name-->Welcome page opens with menubar.
3. Start Navigating through Keyboard inside "File" menuitem.
4. Verify Keyboard focus is shifting oustide the "File" menuitem.

Actual:
Keyboard focus goes outside the "File" menuitem instead of remaining inside, while navigating inside "File" menuitem.

Note:
Same issue is observed for all Menuitems(Edit,View,Insert,Cell...etc) which are present on this page.
Same issue is observed in "Chrome+NVDA" Configuration.
Same issue is observed in Narrator and NVDA.

Expected:
Keyboard focus should remain inside the "File" menuitem, while navigating through "File" menuitem using keyboard.

UserImpact:
Keyboard Only Users face difficulty if Keyboard focus if keyboard focus goes outside the "File" menuitem without closing of dropdown.

Attachment:
(https://github.com/jupyter/notebook/files/2400333/A11y_AzureNotebooks_Jupyter_MenuBar_Keyboard.pptx)

[ednut15]

I would like to confirm the expected behaviour. Should the focus cycle/ wrap around through the chosen menu unless it is closed? Or should it close the menu and move on to the next item on the list e.g. closing the 'File' menu and shifting focus to the Edit menu?

[jtpio]

Closing as there are now different issues tracking accessibility improvements for Jupyter Notebook 7, for example #6800

Thanks!