"No logins found" in Vivaldi Web Panel even though key icon is green

[FlippingBinary]

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• [x] Yes, I tried searching and reviewed the pinned issues

Brief Summary

Vivaldi web browser (Chromium-based) has a web panel feature that allows you to keep web pages in the side panel. These panels share cookies with regular tabs so if a user is logged into a website in a regular tab, the same user is logged in to the website when viewed in the web panel. But, I'm trying to use it to keep a particular website open and authenticated that I don't visit with a regular tab.

Expected Versus Actual Behavior

I expect to see my credentials in the login fields when I click the green key icon, but instead I get the "No logins found" error message. This only happens in the web panel, not a regular tab.

Steps to Reproduce

1. Open Vivaldi web browser.
2. Go to a website with saved credentials and click the green key icon to confirm the credentials autopopulate correctly.
3. Open the sidebar.
4. Click "Add Web Panel" and press enter to create a web panel for the web page.
5. Click the green key icon in the web panel and observe the error.

KeePassXC-Browser Debug Information

KeePassXC - 2.7.10
KeePassXC-Browser - 1.9.8
Operating system: Win64
Browser: Chrome/Chromium 136.0.0.0

[varjolintu]

What does the browser web developer console log say?

[FlippingBinary]

I just noticed that the tooltip says "No credentials to fill" even when the key icon is green in the web panel, but I'm having trouble reproducing the misleading green icon on a website that I can share. The extension can't access the credentials from the web panel for any website, regardless of the key color. That's the larger issue for me. I'll attach a log from refreshing the login page for usajobs.gov and clicking the grey key. It produces an error even though credentials are saved and do work in a regular tab. I don't see anything meaningful in the log. The Permissions-Policy header error is present even in regular tabs, so I don't think that's related and haven't looked into it further.

secure.login.gov-1750265608181.log

[varjolintu]

Your entry has a URL https://secure.login.gov that you use? I'm not sure if this is Vivaldi's way to wrap pages in to a single web page or something similar, but it doesn't seem to be compatible with extension content scripts.

[FlippingBinary]

Yes, that is the URL of the entry and it works just fine in regular Vivaldi browser tabs. The KeePassXC key icon also appears in the username field in the web panel. Isn't that possible only if the extension content script loaded?

[varjolintu]

Yes. Everything else depends on how Vivaldi has implemented that Web Panel. Is it an actual new "window" with separate URL or something else. Maybe I need to test this by myself when I have the time.