This is release is essentially focused on stability and performance. These bug-fixes and improvements have now been included in WordPress 5.3 beta 2.

At the same time, architectural work is continuing to prepare the block content areas editing capabilities.

6.6 🇨🇭

Enhancements

• Turn Stack on mobile toggle on by default in the Media & Text block.
• Only show the Inserter help panel in the topbar inserter.
• Use minimum height instead of height for Cover height control label.
• Update the buttons styling to match core.
• Add preview examples for multiple core blocks.

New APIs

• Implement EntityProvider and use it to refactor the meta block attributes.

Experimental

• Introduce the wp_template custom post type to preempt the block content areas work.
• Use the entities store for the widgets screen.

Bugs

• Fix javascript error potentially triggered when using saveEntityRecord action.
• Avoid marking the post as dirty when forcing an undo level (RichText).
• Fix Post Publish Panel overlapping the user profile dropdown menu.
• Fix and align collapsing logic for Save Draft and Saved button states.
• Remove Reusable block name and description from the inserter help panel.
• Fix spacing issues in the inserter panel previews.
• Gallery block: Don’t show the caption gradient overlay unless image is selected or a caption is set.
• Gallery block: Fix custom alignment layouts
• Fix dirtiness detection when server-side saving filters are used.
• Remove wrong i18n domain.
• Fix invalid block warning panel.
• Fix various issues in related to the BlockDirectory inserter.
• Cover block: Show Height control only if an image background is selected.
• Fix RichText composition input issues.
• Fix block placeholders spacing after Core inputs updates.
• Fix checkbox design (color and background) after Core updates.
• Fix radio buttons design after Core updates.
• Remove any existing subscriptions before adding a new save metaboxes sub to prevent multiple saves.
• Clear auto-draft titles on save if not changed explicitly.
• Fix block error boundary.
• Fix select elements design in the sidebar after Core updates.
• Allow using space with modifier keys at the beginning of list items.
• Fix the inputs height after Core updates.
• fix conflict between remote and local autosaves.

Performance

• Request the Image block’s metadata only if the block is selected.
• Improve the performance of the block reordering animation in Safari.
• Remove Autocomplete component wrappers.

Various

• Replace registered social links blocks if already registered in Core.
• More stable List block e2e tests.
• Add e2e tests to validate the date picker UI behavior.
• Add e2e tests to validate the local auto-save behavior.
• Mark the social links block as experimental.
• Update the e2e tests to accommodate the new theme.
• Align the version of lodash with WordPress core.
• Add phpcs rule to detect unused variables.
• Simplify Block Selection Reducer.
• Add has-background classes to pullquote and Media & Text blocks for consistency.
• Tidy up button vertical align styles.
• Update browserslist dependency.

Documentation

• Add scripts/styles dependency management documentation.
• Update docs with the example property used for Inserter previews.
• Typos and tweaks: 1, 2, 3, 4, 5.

Mobile

• Add rounded corners on media placeholder and unsupported blocks.
• Fix link editing when the cursor is at the beginning of a link.

Performance Benchmark

The following benchmark compares performance for a particularly sizeable post (~ 36000 words, ~ 1000 blocks) over the last releases. Such a large post isn’t representative of the average editing experience but is adequate for spotting variations in performance.

Version	Loading Time	KeyPress event (typing)
Gutenberg 6.6.0	4.7s	38.96ms
Gutenberg 6.5.0	4.68s	42.96ms
WordPress 5.2	5.69s	57.65ms

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👏 Kudos to all the contributors. Thank you.

#core-editor, #editor, #gutenberg