Using just keyboard, user can't get to Running tab on /tree page

[tonyfast]

Focus

Issue Area # 1

• Expectation: All supplementary elements that a user needs to interact with receive keyboard focus and be reached using only the keyboard. (WCAG Criteria 2.1.1 (A))
• Observed:
  • On Tree page, can't get to "Running" tab with just a keyboard. That section or each of those tabs need a tabindex="0" on it.

[tonyfast]

the lumino tabs should implement the ARIA practice guide for tabs. the APG provides recommendations for keyboard patterns, focus, and aria markup.

i'm happy to be a resource for someone implementing this moderately complex aria pattern.

this should likely be transferred to lumino as an accessibility issue.