Green json highlight disappearing when you scroll the prompt

Describe the problem/error/question

When I first open the Agent Node. You can see the green JSON values highlighted but as soon as I start scrolling or doing anything to the Node, it all disappears and I lose the highlight, making it very difficult to edit, especially with long prompts. Anyone else experiencing this? It is a very large workflow with approx 100 nodes could it be that?

What is the error message (if any)?

Please share your workflow


Share the output returned by the last node

Information on your n8n setup

  • n8n version: Version 2.20.7-exp.0
  • Database (default: SQLite): Postgres (supabase)
  • n8n EXECUTIONS_PROCESS setting (default: own, main):
  • Running n8n via (Docker, npm, n8n cloud, desktop app): Render / Supabase
  • Operating system:

hi @jakeThai

i think it might be an interface glitch.
for me it works if i leave it alone after scrolling.

Yes, the expression evaluations may work very slowly with a large number of nodes and or expressions that should be calculated. Better to move part of the flow into a sub-workflow to reduce the usage (every node, expression, and connection is rendered on the client side: your browser)

@jakeThai ur on n8n 2.20.7-exp.0 which is an experimental build — those tend to have UI quirks that get fixed before going to stable. quick test: does the highlight loss still happen if u upgrade to a stable release like 2.21.x? if it persists on stable too, the 100-node workflow size is more likely the cause — long expression fields + heavy canvas render compete for the UI thread. what browser are u on?

I changed it to stable Version 2.22.4 and same issue persist but thanks anyway.

I’m on Brave browser \Windows does that affect anything?

Hey @jakeThai — since upgrading to stable didn’t fix it and you’re on Brave/Windows, a couple of things worth trying:

Brave’s Shields (the built-in ad/tracker blocker) can sometimes interfere with syntax highlighting or script loading in complex web apps like n8n. Try opening the workflow in a Shields-down tab (click the lion icon in the address bar and toggle Shields off for the n8n tab). If the highlighting comes back, that’s the culprit — you can keep Shields off just for n8n.

If that doesn’t help, the 100-node canvas is likely the main issue. n8n renders the entire workflow in the browser, and a large canvas with long expression fields really taxes the UI thread, especially on Windows where GPU acceleration can be spotty across different browsers. A few things that often ease this:

Ā· Use sub-workflows (Execute Workflow node) to break the giant canvas into smaller chunks. It’ll lighten the render load dramatically.

Ā· Brave might not be using hardware acceleration properly — you can check in brave://settings/system. If ā€œUse hardware acceleration when availableā€ is off, turn it on. If it’s already on and you’re still seeing lag, try toggling it and restarting Brave.

Ā· As a quick test, open the same workflow in a Chromium-based browser like Edge or Chrome just to see if the problem is Brave-specific. If it works elsewhere, it’s a rendering issue with your Brave profile/Shields config.

If none of that fixes it, it might be worth reporting on the n8n GitHub as a UI performance bug — the devs are generally responsive to canvas rendering issues with large workflows.

Can you test the same workflow in Chrome or Edge and see if the highlight still disappears there? That would help separate a browser-specific issue from the workflow size/rendering issue people mentioned above.

thank you, same behaviour in Chrome. If anything it’s slightly worse, green highlight shows in Prompt (User Message), several json highlights should be showing in Chat message but no green even though the values are pulled through successfully.

Have also tried shields down in Brave.

ā€˜Use graphics acceleration when available’ setting enabled. This may be what it’s called now there was no 'hardware acceleration; option available.

Yes large workflow is not ideal however it used to work no problem. We are doing high volume so breaking the workflow down would be disruptive, will try to fix first and break down as last resort.

Specific issue, highlight shows at first, as soon as you scroll even a tiny bit highlight disappears and doesnt return.

I will report on Github and post any findings appreciate the help.

Have you tried opening the text and hitting anything? I have the same highlighting issue with my HTML node, which has too much text. However, it starts to display expressions again once I type somethings

interesting it actually does cause the highlight to return if i type a letter, however disappears as soon as i scroll again. also no highlights are showing on Result window so it’s still broken and difficult to use. Thanks anyway

Thanks for testing Chrome and Shields down. Since it happens in both Brave and Chrome, and typing briefly makes the highlighting repaint until you scroll again, this sounds less like a browser setting and more like an editor/rendering bug in the n8n UI.

If you open the GitHub issue, I’d include the exact repro: large workflow, Agent node, Prompt/User Message highlighting disappears after any scroll, typing forces it to repaint, Result/Chat Message highlighting still doesn’t recover, values still execute correctly. A short screen recording would probably make it much easier for the n8n team to confirm.