[UEPR-483] "Choose a Sprite" and "Choose a Backdrop" keyboard accessibility

[kbangelov]

Resolves

https://scratchfoundation.atlassian.net/browse/UEPR-483

Proposed Changes

• Adds keyboard navigation logic.
• UI bug: tooltips don't refresh in case of first open or shift+tab-ing back to the menu.

Reason for Changes

Part of accessibility initiative for Scratch.

[Copilot]

Pull request overview

Improves keyboard accessibility for the “Choose a Sprite” / “Choose a Backdrop” action menus in Scratch GUI as part of the accessibility initiative (UEPR-483).

Changes:

• Refactors ActionMenu from a class component to a hook-based functional component and adds keyboard navigation/focus handling.
• Updates ActionMenu button styling to show focus state similar to hover.
• Minor test/comment and formatting cleanup.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 5 comments.

File	Description
packages/scratch-gui/test/integration/sounds.test.js	Adds a clarifying comment for the keyboard shortcuts integration test.
packages/scratch-gui/src/components/stage-selector/stage-selector.jsx	Removes an extraneous blank line in the moreButtons config.
packages/scratch-gui/src/components/action-menu/action-menu.jsx	Implements keyboard navigation + refactors ActionMenu to hooks/memoization.
packages/scratch-gui/src/components/action-menu/action-menu.css	Adds :focus styling to match hover for action menu buttons.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[adzhindzhi]

Looks good to me! 👍

[KManolov3]

Looks mostly good, left a comment on an edge case. Thanks for migrating the action menu to React hook syntax!

[KManolov3]

Nitpick: there's now an empty line between the comment and the code it's referring to

[KManolov3]

This looks like it slightly differs in behavior from production:

• on production, when we open and close the sprite modal, the action menu is closed
• with this change, when we open and close the sprite modal, the action menu is still open

I am not averse to the updated behavior, as it aligns with the "return focus to previously selected element when you navigate out of a modal".

However there are some visually unpleasant cases:

• if I open the "Upload a sprite" menu from the action button, the menu closes after a timeout, but if I navigate out of the upload dialog which it opens, it reopens the menu, but the label shows on the bottom
• same for other actions

I am open to suggestions for what the most consistent behavior (and the least effort change) would be.

As a fallback, keeping the production behavior (and possibly making sure the inner menu items are also unselected, so that no inconsistent label appears) can be an option for this case (so, blur out of the focused action menu, but keep the focus, so that TAB would return to the same / next item).

[KManolov3]

Additionally, the behavior when clicking "Surprise" has changed here - it unfocuses the action menu entirely, while on production it blurs, but keeps the focus on the menu item.