Description

If you open an email with an attachment, it is no longer possible to access it with a screen reader by going to "Message" in the menu and then to "Attachments". It is also no longer possible to access the attachments with TAB.

Steps to reproduce

1. Select a message with attachment and open it with Enter.
2. Go to "Message" in the menu bar and then to the "Attachments" submenu.

Result

The menu is grayed out even though the message contains an attachment. Navigating through the opened message with TAB also does not get to the attachments.

Expected

The attachments should be accessible from the menu bar as well as with TAB in the message window.

Testing with Thunderbird 113.0a1 20230329 on linux I can verify there is no Attachments submenu inside the message menu when viewing message in a new window. When using tab and shift+tab to navigate in the window a message has been opened in I can focus the list of attachments, I can use up and down arrow keys to navigate and I can use shift+F10 or the applications key to bring up the context menu for individual attachments.
I know some screen reader users were preferring the menu bar access to attachments so most likelly they will feel upset about this change however speaking pure technically the feature is still accessible.
There are some shortcuts to manipulate attachments when writing emails but the easiest way on how to focus attachment list when reading a message is by pressing F6 then shift+tab I think.

(In reply to Peter Vágner from comment #1)

There are some shortcuts to manipulate attachments when writing emails but the easiest way on how to focus attachment list when reading a message is by pressing F6 then shift+tab I think.

With your steps I can access the attachments, however this does not correspond to normal user behavior. No beginner would get the idea to first press F6 and then Shift+TAB. Even I, who actually calls myself an advanced user, only got the idea after your hint.

Many users expect to access attachments via the menu or (similar to Outlook) by pressing Shift+TAB once when in the message reader.

(In reply to Ali Savas from comment #2)

this does not correspond to normal user behavior. No beginner would get the idea to first press F6 and then Shift+TAB.

Well when opening a message reading UI, the message body receives the focus. Screen readers usually switch to browse mode and start reading the content. Exploring this window by pressing tab or shift+tab is something every user that is calling him / her self a computer literate should get familiar with.
I am not saying they have to memorize shortcut key sequences but they should try to understand the navigation paradigms where possible.
Adding a shortcut key that would jump directly to the attachment list would be a nice compromise but that might not be suitable to beginer users as well.
When pressing tab key the focus should jump in the reading order i.e. from left to right and from top to bottom. When pressing shift+tab it should work the other way round.
It's not that difficult to override the taborder but that way we might end up potentially creating suboptimal experience for people with other impairments e.g. those that have issues concentrating on their task or issues with reading the text.
If we would like to satisfy both these cases we'd have to move the file list above the message content below the message header. Ancient outlook express had its UI elements arranged like that and I guess that's when this habit has started.
Again I don't have strong opinion on this my-self I am just thinking out loud.

(In reply to Peter Vágner from comment #3)

(In reply to Ali Savas from comment #2)

this does not correspond to normal user behavior. No beginner would get the idea to first press F6 and then Shift+TAB.

Adding a shortcut key that would jump directly to the attachment list would be a nice compromise but that might not be suitable to beginer users as well.

Yes, actually it is. If you tell them that. In my opinion, it would be exactly what would be best for beginners. There are indeed users who have difficulty remembering a string of keys. There were already users who had difficulties to get to the attachments via the menu. These users also don't have the capacity and therefore don't want to remember the screen layout. Most of them just want to press an easy to remember keystroke and get where they want to go. Something like this also falls under the term "accessibility". Just because something works technically and is easy to get to doesn't mean it's a good solution for everyone.

I work with a lot of blind people and give them computer and JAWS training, and unfortunately I always notice that there are people who can't understand things when they get a little more complex. For many people it should just work.

Please don't get me wrong, I personally have no problem with remembering these steps to get to the attachments.

If it were up to me, I would be all for setting up a keyboard shortcut for attachments. It wouldn't bother anyone and everyone could work the way they want.