What?

When a Gallery block has lightbox enabled, clicking or tapping the expanded image inside the lightbox overlay no longer dismisses the dialog.

Closes #78869.

Why?

WordPress 7.0 introduced navigation controls (Previous / Next) for the Gallery lightbox (#62906). With those controls present, the image-click-to-close behaviour inherited from the standalone Image block became a UX problem: users tapping the image to inspect detail—or slightly mis-tapping while reaching for a navigation button—would accidentally dismiss the
lightbox with no way to recover other than reopening and navigating back.

On touch devices this is especially disruptive because hover isn't available and the image is the most prominent tap target in the overlay. This was also raised in #77545 and #55513.

How?

Added a new handleOverlayClick action in view.js that wraps the existing hideLightbox action:

• When navigation is present (gallery), it checks if the clicked element is an IMG or FIGURE. If the click originated on the image, it returns early. If the click landed directly on the overlay backdrop, scrim, or Close button, it proceeds to hideLightbox.
• When navigation is absent (standalone image), the guard is skipped and hideLightbox is called normally—no behaviour change.
• Escape key calls hideLightbox directly and is completely unaffected.
• Close button triggers handleOverlayClick but since it is a <button> and not an <img>, it correctly dismisses the lightbox. The index.php lightbox overlay template is updated to bind the click event to the new handleOverlayClick instead of hideLightbox.

Testing Instructions

1. Add a Gallery block (≥ 2 images) and enable lightbox.
2. Click an image to open the lightbox.
3. Click / tap the expanded image → dialog stays open.
4. Click the backdrop (area outside the image) → dialog closes.
5. Press Escape → dialog closes.
6. Click the Close button → dialog closes.
7. Repeat with a standalone Image block (single image, no gallery) → clicking the image still closes the lightbox as before.

Screenshots or screencast