fix(button): double tab navigation when clicking button/action-button with href and target="_blank"

[Rajdeepc]

Description

Fixes an issue where clicking sp-button or sp-action-button with href and target="_blank" attributes opened two browser tabs in Chrome instead of one.

Root cause

The ButtonBase component renders an anchor element with position: absolute; inset: 0 that overlays the entire button. When clicked:

1. handleClickCapture catches the click and calls shouldProxyClick() → anchorElement.click() → first navigation
2. The original click event continues propagating and naturally reaches the anchor → second navigation

This only manifested in Chrome due to how it handles click event propagation on absolutely-positioned elements within shadow DOM.

Solution

Check if the anchor element is already in the click event's composedPath() before triggering a proxy click. If the anchor is in the path, the browser will handle navigation naturally and no proxy is needed.

const path = event?.composedPath() || [];
if (path.includes(this.anchorElement)) {
    return false;  // Skip proxy - browser handles it naturally
}

Motivation and context

Related issue(s)

• fixes [SWC-921]

Screenshots (if appropriate)

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Author's checklist

• I have read the CONTRIBUTING and PULL_REQUESTS documents.
• I have reviewed at the Accessibility Practices for this feature, see: Aria Practices
• I have added automated tests to cover my changes.
• I have included a well-written changeset if my change needs to be published.
• I have included updated documentation if my change required it.

---

Reviewer's checklist

• Includes a Github Issue with appropriate flag or Jira ticket number without a link
• Includes thoughtfully written changeset if changes suggested include patch, minor, or major features
• Automated tests cover all use cases and follow best practices for writing
• Validated on all supported browsers
• All VRTs are approved before the author can update Golden Hash

Manual review test cases

• Modifier Clicks

  1. Go here
  2. Cmd+Click, Ctrl+Click
  3. Expect it to open a single new tab and not double

• VO testing

  1. Go here
  2. CMD + F5 to enable, VO + Space to activate
  3. Expect it calls out as "link"

• Keyboard Testing

  1. Go here
  2. Tab to focus, Enter/Space to activate
  3. Expect it calls out as "link"

Device review

• Did it pass in Desktop?
• Did it pass in (emulated) Mobile?
• Did it pass in (emulated) iPad?

[changeset-bot]

⚠️ No Changeset found

Latest commit: d98a19c

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[github-actions]

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🔍 First Generation Visual Regression Test Results

When a visual regression test fails (or has previously failed while working on this branch), its results can be found in the following URLs:

• Spectrum | Light | Medium | LTR
• Spectrum | Dark | Large | RTL
• Express | Light | Medium | LTR
• Express | Dark | Large | RTL
• Spectrum-two | Light | Medium | LTR
• Spectrum-two | Dark | Large | RTL
• High Contrast Mode | Medium | LTR

Deployed to Azure Blob Storage: pr-5937

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