Editor: Add Inspector and use radios in the Panels menu

[ciampo]

Follow-up to the discussion in #83993.

What?

Add Inspector to the Panels submenu and use radios to select the active panel. Inspector is selected when either the document or block inspector is open. Keep Panels hidden when Inspector is the only available panel.

Why?

In the site editor, Panels can contain only an unchecked Styles item while Inspector is open. Listing Inspector makes the active panel clear and gives the submenu two choices. A plain post editor with no plugin panels does not need the submenu.

How?

Use the shared editor menu for the post editor and both site editor versions. Keep the existing plugin menu items, and render the submenu only when another panel contributes an item. Omit Inspector in distraction-free mode, which hides the sidebar.

Selecting an active radio keeps its panel open. Selecting Inspector from another panel opens the document or block inspector according to the current block selection. Closing the sidebar with its close button leaves no radio selected.

Remove the obsolete @wordpress/interface type shim from the Vitest validator so the menu tests use the package's actual store types.

Testing Instructions

1. Open a template in the site editor with Settings open. Open Options → Panels. Inspector should be checked and Styles unchecked.
2. Choose Styles, then reopen Panels. Styles should be checked and Inspector unchecked. Choose Inspector to switch back.
3. Select the active Inspector or Styles radio again. Confirm its panel stays open. Close the sidebar with its close button, reopen Panels, and confirm neither radio is selected. Choose Inspector to reopen it.
4. Select a block, switch to Styles, then choose Inspector. The block inspector should open.
5. Open a plain post with no plugin sidebars. Confirm Options has no Panels submenu and the toolbar Settings button still opens and closes Inspector. With a plugin sidebar registered, confirm Panels contains Inspector and the plugin radio. Selecting the active plugin radio again should keep its sidebar open.
6. With a plugin sidebar registered, enable Options → Appearance → Distraction free. Confirm Panels keeps the plugin items and omits Inspector. Disable Distraction free and confirm Inspector returns checked.
7. Repeat the template checks with the Extensible Site Editor experiment enabled.

Testing Instructions for Keyboard

1. Focus Options and press Enter. Use the arrow keys to reach Panels, then press Right Arrow to open it.
2. Use Up and Down Arrow to move between Inspector and Styles. Press Enter to activate an item. Confirm its panel opens and focus returns to Options. Activate the selected radio again and confirm the panel stays open.
3. Reopen Panels. Press Escape to return to Panels, then Escape again to return to Options.

Screenshots or screencast

Before: Inspector open, only Styles listed	After: Inspector listed and checked

Styles open	Post editor: Inspector is the only panel

Verification

The production build, type check, changed-file JavaScript lint, changelog validation, and full Vitest convention check passed. All 39 menu tests passed. Native browser checks covered both site editor versions, the post editor, and keyboard selection and reselection of a real plugin sidebar.

The Panels adapter opts default complementary-area items into radios. Older hosts, older interface fills, and explicit checkbox overrides retain checkbox toggles. Generic plugin actions and links remain menu items. The interface package documents the selection behavior.

Use of AI Tools

Codex assisted with investigation, implementation, regression tests, verification, and this description.

[github-actions]

🤖 PR meta 🤖

🎉 Props

If you're merging code through a pull request on GitHub, copy and paste the following into the bottom of the merge commit message.

Co-authored-by: ciampo <mciampini@git.wordpress.org>
Co-authored-by: Mamaduka <mamaduka@git.wordpress.org>
Co-authored-by: jasmussen <joen@git.wordpress.org>

To understand the WordPress project's expectations around crediting contributors, please review the Contributor Attribution page in the Core Handbook.

Updated as activity occurs, without notifying anyone named here. Add the props-bot label to refresh.

📦 Bundle size

Size Change: +538 B (+0.01%)

Total Size: 8.25 MB

📦 View Changed

Filename	Size	Change
build/scripts/edit-widgets/index.min.js	67.1 kB	+63 B (+0.09%)
build/scripts/editor/index.min.js	616 kB	+475 B (+0.08%)

_{19018ad Run}

⚡ Performance

Show the results

Client side metrics exclude the server response time.

front-end-block-theme

Metric	ab900ab	trunk	% Change
timeToFirstByte	61.55 ms +8.85% -7.96%	58.25 ms +8.5% -4.29%	5.67%
largestContentfulPaint	100 ms +12% -4%	96 ms +4.17% -4.17%	4.17%
lcpMinusTtfb	39.85 ms +15.81% -8.78%	34.8 ms +13.36% -4.74%	14.51%
wpBeforeTemplate	30.52 ms +14.19% -7.27%	28.68 ms +10.84% -1.53%	6.42%
wpTemplate	25.42 ms +2.75% -4.64%	25.01 ms +4.72% -4.48%	1.64%
wpTotal	57.31 ms +7.94% -7.56%	54.46 ms +8.94% -4.63%	5.23%
wpMemoryUsage	7.63 MB +0% -0%	7.59 MB +0% -0%	0.46%
wpDbQueries	17 +0% -0%	17 +0% -0%	0%

front-end-classic-theme

Metric	ab900ab	trunk	% Change
timeToFirstByte	49.75 ms +5.33% -1.21%	48.75 ms +3.28% -2.56%	2.05%
largestContentfulPaint	108 ms +3.7% -3.7%	104 ms +1.92% -0%	3.85%
lcpMinusTtfb	57.6 ms +2.69% -3.82%	55.55 ms +2.52% -2.61%	3.69%
wpBeforeTemplate	27.43 ms +4.08% -1.68%	26.72 ms +4.08% -2.25%	2.66%
wpTemplate	18.85 ms +2.12% -2.28%	18.15 ms +5.62% -1.76%	3.86%
wpTotal	46.52 ms +5.22% -1.61%	45.68 ms +3.02% -2.76%	1.84%
wpMemoryUsage	6.25 MB +0% -0%	6.21 MB +0% -0%	0.71%
wpDbQueries	14 +0% -0%	14 +0% -0%	0%

media-processing

Metric	ab900ab	trunk	% Change
mediaProcessingJpeg	400.66 ms +1.07% -0.2%	405.16 ms +0.84% -0.24%	-1.11%
mediaProcessingAvif	6089.49 ms +0.25% -0.35%	6085.93 ms +0.29% -0.19%	0.06%
mediaProcessingJpegToAvif	4201.14 ms +0.52% -0.48%	4196.89 ms +0.1% -0.2%	0.1%

media-upload

Metric	ab900ab	trunk	% Change
jpegUploadProcessing	1709.71 ms +14.81% -16.67%	1430.73 ms +1.66% -0.79%	19.5%
pngUploadProcessing	220.2 ms +2.23% -13.83%	205.78 ms +15.95% -11.5%	7.01%
largeJpegUploadProcessing	1420.03 ms +0.63% -0.7%	1418.85 ms +0.98% -0.94%	0.08%
multipleImageUploadProcessing	1609.71 ms +8.78% -1.38%	1610.73 ms +26.98% -0.71%	-0.06%

post-editor

Metric	ab900ab	trunk	% Change
serverResponse	416.77 ms +4.59% -7.14%	410.22 ms +2.49% -2.33%	1.6%
firstPaint	218.6 ms +13.46% -11.99%	207.51 ms +36.34% -14.26%	5.34%
domContentLoaded	1011.75 ms +3% -1.83%	974.98 ms +0.64% -1.68%	3.77%
loaded	1012.98 ms +2.99% -1.85%	976.17 ms +0.66% -1.69%	3.77%
firstContentfulPaint	424.74 ms +2.18% -0.74%	408.39 ms +2.56% -1.71%	4%
firstBlock	2891.5 ms +0.94% -2.01%	2780.76 ms +1.89% -0.26%	3.98%
type	17.85 ms +1.85% -2.63%	17.16 ms +7.23% -2.51%	4.02%
typeWithoutInspector	16.99 ms +5.41% -3.77%	17.16 ms +2.97% -5.36%	-0.99%
typeWithTopToolbar	22.51 ms +0.84% -1.24%	21.94 ms +2.78% -5.42%	2.6%
typeContainer	8.49 ms +7.18% -1.88%	8.39 ms +3.69% -7.51%	1.19%
focus	69.81 ms +4.97% -5.41%	68.62 ms +10.27% -4.02%	1.73%
firstFocus	187.75 ms +0% -0%	186.47 ms +0% -0%	0.69%
selectAll	402.19 ms +1.77% -0.51%	387.69 ms +5.49% -3.43%	3.74%
listViewOpen	55.94 ms +6.58% -1.23%	55.04 ms +8.28% -12.63%	1.64%
inserterOpen	22.61 ms +8.67% -10.35%	22.62 ms +23.03% -8.09%	-0.04%
inserterHover	2.17 ms +6.91% -1.84%	2.11 ms +15.64% -11.37%	2.84%
inserterSearch	7.93 ms +17.78% -3.78%	8.74 ms +6.86% -14.19%	-9.27%
loadPatterns	652.26 ms +10.29% -2.79%	647.77 ms +7.8% -2.28%	0.69%
wpTotal	406.55 ms +4.65% -7.34%	400.37 ms +2.15% -2.58%	1.54%
wpMemoryUsage	13.18 MB +0% -0%	13.14 MB +0% -0%	0.28%
wpDbQueries	54 +0% -1.85%	54 +0% -0%	0%

site-editor

Metric	ab900ab	trunk	% Change
serverResponse	518.85 ms +3.1% -5.41%	521.49 ms +2.16% -7.19%	-0.51%
firstPaint	257.01 ms +75.98% -12.37%	265.98 ms +15.06% -14.4%	-3.37%
domContentLoaded	1171.05 ms +3.19% -1.19%	1187.42 ms +1.38% -1.64%	-1.38%
loaded	1172.49 ms +3.16% -1.2%	1188.71 ms +1.38% -1.64%	-1.36%
firstContentfulPaint	471.87 ms +2.43% -3.71%	468.68 ms +2.19% -1.68%	0.68%
firstBlock	4375.7 ms +0.4% -0.84%	4287.21 ms +0.34% -0.62%	2.06%
type	18.87 ms +4.29% -3.71%	18.6 ms +3.82% -7.69%	1.45%
navigate	122.01 ms +6.75% -6.97%	127.74 ms +6.78% -4.52%	-4.49%
loadPatterns	1378.78 ms +19.15% -4.65%	1416.87 ms +2.3% -8.32%	-2.69%
loadPages	1095.05 ms +1.5% -0.69%	1058.67 ms +4.12% -0.82%	3.44%
wpTotal	508.82 ms +3.27% -5.5%	511.87 ms +2.08% -7.4%	-0.6%
wpMemoryUsage	12.14 MB +0% -0%	12.10 MB +0% -0%	0.3%
wpDbQueries	43 +2.33% -0%	43 +2.33% -0%	0%

_{19018ad Run}

[Mamaduka]

Maybe we should just remove Styles from the panels submenu. I think it ended up there by accident; we've floated the idea of removing it a couple of times. cc @youknowriad, @jasmussen

P.S. There's also an easy way to add Settings to the Panels submenu. Just add name={ tabName } to PluginSidebar in packages/editor/src/components/sidebar/index.jsx.

[ciampo]

I'll wait for "product" feedback re. whether we want to keep "Styles" in the panels submenu at all, before making further code changes

[jasmussen]

Not feeling strongly about this. But "Panels" is what we call any sidebar. The inspector panel, the styles panel, or anything a plugin adds. It's possible we omitted these because we needed to save space in the dropdown, but if we do go in the direction of a flyout, then it seems useful to include every available panel so you know the behavior: that selecting another panel closes the one you already have open.

[ciampo]

if we do go in the direction of a flyout, then it seems useful to include every available panel so you know the behavior: that selecting another panel closes the one you already have open.

This was the angle I approach this PR — mentioning all panels in that submenu would make it more complete / correct, and would remove some awkwardness (one extra entry in the submenu, higher likelihood that there is a checked item in the panel)