Widget toolbar listbox has no accessible name

[vvallalta-code]

Summary

The widget contextual toolbar is exposed as a listbox without an accessible name. Assistive technology announces a listbox but provides no context for what the options control.

Location

• Package: @paperbits/core
• Template: src/ko/ui/defaultViewManager.html
• Current element: <div role="listbox" class="fixed toolbox toolbox-horizontal toolbox-context" ...>

Expected behavior

The listbox has a stable, descriptive accessible name derived from visible context or an explicit labeling contract.

Acceptance criteria

• Add an accessible name to the widget toolbar listbox using aria-label or aria-labelledby.
• Ensure the name remains correct for the active widget/context.
• Preserve existing listbox keyboard and selection behavior.
• Verify the listbox name in the accessibility tree and with a screen reader.

Tracking: Azure DevOps 26085794