Clarify best practice for making content-only dialogs accessible
It’s not currently clear how to best make dialogs like the one below, which only have content and have no interactive widgets, accessible. So far, accessibility support (to get them read out by Orca, for example) has come from marking all the widgets as focusable=true. However, these widgets do not access keyboard/mouse input so shouldn’t technically be focusable. Marking them as focusable results in a big blue focus ring being drawn on them, which is distracting for sighted users.
Apparently Orca has two ways of navigating a UI: focus or flat review. Perhaps there could be a best practice documented for how to trigger Orca to use flat review mode for a dialog. Or a way to annotate the dialog with a lump of accessible text ‘intro’ which would get read out when the dialog is opened.
A hacky kind of middle ground might be to say that such widgets should be focusable=true, but provide a way in GTK to skip rendering the big blue focus ring until the user actually starts to use keyboard nav in that dialog.
Examples of situations where this is relevant: the app context dialogs in gnome-software (which show what permissions / file storage / device access / etc. an app will require; see gnome-software!1970); or a welcome page in an app.