STR

• Set screenshots.browser.component.enabled to true
• Navigate to https://bugzilla.mozilla.org/home (or any webpage)
• Use keyboard shortcut (Ctrl + Shift + S on Windows) to activate Screenshots

Expected:

• It should be possible to page up/down or navigate through the sections and headings on the page from the keyboard in order to change what is visible and will be captured in the screenshot

Actual

• It seems impossible to affect the document's scroll offsets from the keyboard while the Screenshots UI is active/visible.

This seems true for normal keyboard-driven interaction as well as from NVDA. Arguably the user could make these scroll adjustments before activating Screenshots, but for non-keyboard pointer users it is still possible to scroll up and down while the Screenshots UI is active/visible so requiring parity for keyboard a11y seems reasonable.

There is a whole class of bugs we are actively trying to avoid by limiting interaction with the document while Screenshots is active. We'd prefer users not click links, interact with forms etc. in this state, making Screenshots modal-ish. But if we have to choose between that and keyboard navigation & scrolling I'd prefer the latter.

Strictly speaking, this is an access-s2 because something that is accessible to mouse users is not accessible to keyboard or screen reader users. Pragmatically, this is going to be very difficult to do well, especially since there aren't really well established patterns for doing stuff like this, so I'm going to mark it access-s3.