UI Patterns
Tooltip
Must be triggerable by focus (not just hover). Dismissible with Escape. Persistent while hovering over it. Use aria-describedby to associate with trigger. Avoid for critical information.
In plain terms
Little hover hints must also appear on keyboard focus and be easy to dismiss — and should never hide essential information.
Why this matters
Hover-only tooltips are invisible to keyboard users and often to touchscreen users, and tooltips that vanish or can't be reached trip up people with low vision or motor difficulties.
How to detect
Quick check
Tab to the trigger — does the tooltip appear on focus, not just hover? Can you move the pointer onto it without it vanishing, and dismiss it with Escape? Never put essential information only in a tooltip.