Media Editor: Fix pan drag flooding undo history after wheel zoom

[ramonjd]

What?

Stops a pan drag in the media editor from filling the undo history with one entry per frame.

😱 😱 😱 😱 😱 😱 😱 😱

2026-09-28.14.23.59.mp4

😱 😱 😱 😱 😱 😱 😱 😱

😃 😃 😃 😃 😃 😃 😃 😃

2026-09-28.14.37.27.mp4

😃 😃 😃 😃 😃 😃 😃 😃

Why?

Wheel zoom ends its gesture on a 300ms debounce timer.

If you start dragging inside that window, the drag shares the still-open gesture, the timer closes it mid-drag, and every remaining pan frame records its own undo entry.

How?

InteractionController.handlePointerDown now ends a pending wheel gesture (clears the timer, fires onGestureEnd) before starting the drag's gesture. Zoom then pan gives two undo steps: the zoom and the pan.

Testing Instructions

1. Insert an Image block with an uploaded image, select it, and click Edit image in the toolbar.
2. Drag the fine rotation ruler to about -45°.
3. Scroll to zoom on the canvas, then immediately click and drag to pan. Keep dragging for a second or so.
4. Repeat step 3 a few times.
5. Undo repeatedly. Each zoom and each pan should undo in a single step. On trunk, the pan undoes in dozens of small steps.
6. Check that a slow zoom, a pan on its own, and rotation still each undo as one step.

[github-actions]

🤖 PR meta 🤖

📦 Bundle size

Size Change: +19 B (0%)

Total Size: 8.23 MB

📦 View Changed

Filename	Size	Change
build/scripts/editor/index.min.js	614 kB	+19 B (0%)

_{1ffd578 Run}

⚡ Performance

Show the results

Client side metrics exclude the server response time.

front-end-block-theme

Metric	01ed49e	trunk	% Change
timeToFirstByte	56.55 ms +10.79% -2.21%	57.3 ms +15.27% -3.84%	-1.31%
largestContentfulPaint	96 ms +4.17% -4.17%	92 ms +13.04% -4.35%	4.35%
lcpMinusTtfb	35.7 ms +23.81% -6.3%	34.7 ms +18.44% -5.19%	2.88%
wpBeforeTemplate	28.45 ms +10.12% -1.44%	29.1 ms +13.85% -3.02%	-2.23%
wpTemplate	24.73 ms +1.5% -4.69%	24.3 ms +2.3% -4.16%	1.77%
wpTotal	52.92 ms +11.19% -2%	53.57 ms +14.52% -3.51%	-1.21%
wpMemoryUsage	7.61 MB +0% -0%	7.57 MB +0% -0%	0.51%
wpDbQueries	17 +0% -0%	17 +0% -0%	0%

front-end-classic-theme

Metric	01ed49e	trunk	% Change
timeToFirstByte	47.75 ms +7.54% -1.05%	42.5 ms +5.88% -1.18%	12.35%
largestContentfulPaint	104 ms +0% -3.85%	92 ms +0% -4.35%	13.04%
lcpMinusTtfb	54.5 ms +3.67% -3.94%	46.8 ms +4.06% -1.82%	16.45%
wpBeforeTemplate	26.91 ms +11.59% -1.37%	26.2 ms +3.24% -2.37%	2.71%
wpTemplate	17.85 ms +2.18% -0.95%	13.58 ms +1.84% -1.33%	31.44%
wpTotal	44.77 ms +7.42% -1.43%	39.81 ms +5.58% -1.46%	12.46%
wpMemoryUsage	6.22 MB +0% -0%	6.05 MB +0% -0%	2.86%
wpDbQueries	14 +0% -0%	10 +0% -0%	40%

media-processing

Metric	01ed49e	trunk	% Change
mediaProcessingJpeg	395.68 ms +3.18% -0.64%	392.27 ms +3.12% -1.28%	0.87%
mediaProcessingAvif	6052.33 ms +0.25% -0.11%	6053.03 ms +0.05% -0.14%	-0.01%
mediaProcessingJpegToAvif	4158.8 ms +0.54% -0.28%	4177.81 ms +0.5% -0.2%	-0.46%

media-upload

Metric	01ed49e	trunk	% Change
jpegUploadProcessing	1437.82 ms +35.2% -2.12%	1420.49 ms +0.61% -0.1%	1.22%
pngUploadProcessing	183.86 ms +18.26% -8.65%	173.43 ms +27.05% -4.71%	6.01%
largeJpegUploadProcessing	1406.13 ms +0.59% -0.3%	1411.55 ms +0.53% -0.8%	-0.38%
multipleImageUploadProcessing	1559.1 ms +1.11% -1.44%	1556.58 ms +1.07% -0.78%	0.16%

post-editor

Metric	01ed49e	trunk	% Change
serverResponse	401.73 ms +9.13% -2.86%	408.07 ms +8.38% -3.17%	-1.55%
firstPaint	234.96 ms +12.32% -11.2%	251.08 ms +14.26% -13.19%	-6.42%
domContentLoaded	1034.47 ms +1.48% -1.46%	1035.87 ms +1.48% -3.05%	-0.14%
loaded	1035.64 ms +1.5% -1.45%	1037 ms +1.5% -3.04%	-0.13%
firstContentfulPaint	425.85 ms +2.12% -1.72%	424.13 ms +3.39% -4.35%	0.41%
firstBlock	3061.2 ms +1.25% -1.05%	3042.72 ms +1.86% -0.89%	0.61%
type	17.37 ms +7.83% -1.84%	17.65 ms +5.78% -3.12%	-1.59%
typeWithoutInspector	16.56 ms +3.2% -1.69%	17 ms +4.29% -1.59%	-2.59%
typeWithTopToolbar	22.2 ms +3.33% -2.03%	22.28 ms +3.59% -1.97%	-0.36%
typeContainer	8.21 ms +5.48% -11.45%	8.31 ms +8.18% -6.62%	-1.2%
focus	75.71 ms +4% -2.79%	68.79 ms +13.33% -2.46%	10.06%
firstFocus	197.47 ms +0% -0%	201.15 ms +0% -0%	-1.83%
selectAll	446.84 ms +3.55% -1.28%	472.19 ms +1.12% -2.63%	-5.37%
listViewOpen	61.67 ms +3.53% -9.28%	61.55 ms +5.41% -10.97%	0.19%
inserterOpen	23.72 ms +11.55% -13.83%	24.79 ms +4.92% -11.94%	-4.32%
inserterHover	2.07 ms +12.08% -7.73%	2.21 ms +5.88% -12.22%	-6.33%
inserterSearch	8.26 ms +4.72% -2.91%	8.11 ms +12.95% -2.59%	1.85%
loadPatterns	686.7 ms +0.56% -1.22%	654.98 ms +1.78% -4.08%	4.84%
wpTotal	391.99 ms +9.41% -2.87%	398.39 ms +8.62% -3.23%	-1.61%
wpMemoryUsage	13.14 MB +0% -0%	13.11 MB +0% -0%	0.28%
wpDbQueries	54 +0% -0%	54 +0% -1.85%	0%

site-editor

Metric	01ed49e	trunk	% Change
serverResponse	518.29 ms +0.98% -8.63%	506.08 ms +5.79% -4.1%	2.41%
firstPaint	251.21 ms +7.83% -10.33%	240.93 ms +4.11% -8.21%	4.27%
domContentLoaded	1139.75 ms +1.46% -1.24%	1141.67 ms +0.52% -0.83%	-0.17%
loaded	1141.04 ms +1.45% -1.21%	1142.98 ms +0.51% -0.84%	-0.17%
firstContentfulPaint	459.16 ms +1.75% -2.31%	452.07 ms +1.91% -1.96%	1.57%
firstBlock	4154.22 ms +0.46% -0.93%	4159.79 ms +1.86% -0.3%	-0.13%
type	19.08 ms +4.77% -9.28%	16.93 ms +12.34% -1.12%	12.7%
navigate	116.48 ms +17.58% -4.52%	112.42 ms +14.59% -4.23%	3.61%
loadPatterns	1320.22 ms +10.74% -4.82%	1354.58 ms +6.16% -3.28%	-2.54%
loadPages	1069.86 ms +2.37% -2.5%	1069.42 ms +2.11% -1.42%	0.04%
wpTotal	508.67 ms +0.98% -8.83%	495.61 ms +6.12% -4.1%	2.64%
wpMemoryUsage	12.11 MB +0% -0%	12.09 MB +0% -0%	0.13%
wpDbQueries	43 +2.33% -0%	43.5 +1.15% -1.15%	-1.15%

_{1ffd578 Run}

🏁 Flaky tests

Show the failures

Some tests passed with failed attempts. The failures may not be related to this commit but are still reported for visibility. See the documentation for more information.

should update the URL from the last navigation if only varies in the URL fragment in /test/e2e/specs/interactivity/router-navigate.spec.ts, passed after 1 failed attempt.

Error: expect(locator).toHaveText(expected) failed

Locator:  getByTestId('title')
Expected: "Link 1"
Received: "Main"
Timeout:  5000ms

Call log:
  - Expect "toHaveText" getByTestId('title') with timeout 5000ms
  - waiting for getByTestId('title')
    14 × locator resolved to <h2 data-testid="title">Main</h2>
       - unexpected value "Main"

    at /home/runner/work/gutenberg/gutenberg/test/e2e/specs/interactivity/router-navigate.spec.ts:160:25

_{1ffd578 Run}

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Co-authored-by: ramonjd <ramonopoly@git.wordpress.org>
Co-authored-by: andrewserong <andrewserong@git.wordpress.org>

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[andrewserong]

Oh good catch, it's very common to start panning within a close timeframe from ending a mousewheel so this is a good one to fix!

✅ Confirmed that on trunk pans within the debounced window create numerous individual undo entries
✅ Confirmed that this PR correctly closes out the mousewheel changes and the subsequent pan is treated as a single entry
✅ Test coverage looks good

LGTM! 🚀

[ramonjd]

Thanks for the quick test!

[ramonjd]

While testing this I found another one we missed while implementing pixel snap:

• Media Editor: Stop the crop pixel snap from recording undo history #83571