[EuiToolTip] Improve tooltip group transition

[weronikaolejniczak]

Previously reverted on #9748 to derisk a release due to changes needed: elastic/kibana#274383

It was already reviewed and tested, it's good to smoke-test and go again.

Summary

Adjacent EuiToolTip triggers show visually disjoint tooltips. They re-play entry fade-in animation on every hover (~150ms delay + ~90ms fade).

Most design systems solve this by skipping the entry animation within a certain window of time. The show and hide stays synchronous (no timer), preserving the screen-reader behavior from #9626.

The anchor now listens with non-bubbling onMouseEnter/onMouseLeave instead of onMouseOver/onMouseOut. This removes the old relatedTarget filtering that was supposed to fix a flicker where the tooltip could hide when the cursor moved between inner children of the trigger.

Inline animation: none must be on first popover render, not after positionToolTip, otherwise CSS keyframes fire briefly before override.

API Changes

N/A

Screenshots

Impact Assessment

Note: Most PRs should be tested in Kibana to help gauge their Impact before merging.

• 🔴 Breaking changes — What will break? How many usages in Kibana/Cloud UI are impacted?
• 💅 Visual changes — May impact style overrides; could require visual testing. Explain and estimate impact.
• 🧪 Test impact — May break functional or snapshot tests (e.g., HTML structure, class names, default values).
• 🔧 Hard to integrate — If changes require substantial updates to Kibana, please stage the changes and link them here.

Impact level: 🟢 Low

• VRTs are unaffected (it's an animation change),
• there is impact for consumers: nested tooltips now won't work as expected by consumers because of no bubbling. Only internal tooltip will be shown.

Prepped changes: Kibana PR

Release Readiness

• Documentation: {link to docs page(s)}
• Figma: {link to Figma or issue}
• Migration guide: {steps or link, for breaking/visual changes or deprecations}
• Adoption plan (new features): {link to issue/doc or outline who will integrate this and where}

QA instructions for reviewer

Behavior

• There's only ever one tooltip at a time (potential regression to the tooltip manager original intent)
• When triggers are next to each other, hovering over them skips animation
• When triggers are further from each other, hovering over them plays the full animation
• There is no flickering
• Turn reduced motion setting on and make sure tooltip displays correctly

Screen readers

• VO + Chrome announces tooltips reliably (potential regression)
• VO + Safari announces tooltips reliably (potential regression)
• NVDA announces tooltips reliably (potential regression)
• JAWS announces tooltips reliably (potential regression)

Checklist before marking Ready for Review

• Filled out all sections above
• QA: Tested light/dark modes, high contrast, mobile, Chrome/Safari/Edge/Firefox, keyboard-only, screen reader
• QA: Tested in CodeSandbox and Kibana
• QA: Tested docs changes
• Tests: Added/updated Jest, Cypress, and VRT
• Changelog: Added changelog entry
• Breaking changes: Added breaking change label (if applicable)

Reviewer checklist

• Approved Impact Assessment — Acceptable to merge given the consumer impact.
• Approved Release Readiness — Docs, Figma, and migration info are sufficient to ship.

[elastic-vault-github-plugin-prod]

2 visual difference(s) found - expand to review, then click Approve visual changes to update baselines

euicodeblock (1 difference)

Story	Before	After	Diff
virtualized code block scrolling desktop

euidatagrid (1 difference)

Story	Before	After	Diff
render custom toolbar desktop

[elastic-vault-github-plugin-prod]

2 visual difference(s) found - expand to review, then click Approve visual changes to update baselines

euidatagrid (2 differences)

Story	Before	After	Diff
compact desktop
render custom toolbar desktop

[elasticmachine]

💚 Build Succeeded

• Buildkite Build
• Commit: f0aabe3

History

• 💚 Build #6864 succeeded f5e051b

cc @weronikaolejniczak

[elasticmachine]

💚 Build Succeeded

• Buildkite Build
• Commit: f0aabe3
• Documentation website
• Storybook
• 🚫 Visual regression tests skipped (remove the skip-vrt label to re-enable)

History

• 💔 Build #3981 failed f5e051b
• 💔 Build #3980 failed f5e051b

cc @weronikaolejniczak