[Bug]: Side bar web panel doesn't work when a container is assigned to a page

[gmsh]

Pre-Submission Checklist

• [X] I have checked the existing/closed issues to ensure this issue has not already been reported.
• [X] I am using the latest supported version of the browser.
• [X] I have tried disabling all browser extensions/add-ons to rule out interference from these.
• [X] I have tried clearing the browser cache and cookies.
• [X] I have checked with a new profile and the issue still occurs.
• [X] I have provided detailed step-by-step instructions on how to reproduce the issue.
• [X] I have included relevant screenshots or console outputs.
• [X] I have checked that this problem is not occurring in the latest version of Firefox ESR.
• [X] This issue is specific to this browser and does not occur in other browsers.

Bug Summary

1. If you have installed the Firefox Multi-Account Containers addon and assign a page to always open this site in a specific container, the same page won't open in the sidebar web panel.
2. In the Web Panel Settings, the Use the following Container drop-down box does not display the list of containers.

Reproduction Steps

Taking this page https://docs.ablaze.one/floorp_privacy_policy/ as an example, here is the steps to reproduce the issue:

Step 1. install the Firefox Multi-Account Containers addon.

Step 2. open the page https://docs.ablaze.one/floorp_privacy_policy/ and click the Firefox Multi-Account Containers addon icon, then select always open this site in.

Step 3 . assign a container, say the test in the following screenshot

Step 4. click the add button to add the page to the side bar web panel:

Step 5. click save changes button. BTW, the use the following container is empty, which is also unexpected.

Step 6. click the new added icon in the side bar, you get an empty page

Expected Behavior

1. the Use the following Container drop-down box should show the list of containers
2. the page should not be empty if it is assigned to a container by always open this site in menu.

Actual Behavior

both the Use the following Container drop-down box and the side bar web panel don't work as expected.

Screenshots

I've included the screenshots in the previous sections.

Browser Version

11.17.1

Operating System

macOS 14.6.1

Additional Context

The previous ESR115 based versions don't have this bug. This bug is reproducible in a clean profile.

[surapunoyousei]

Thanks, I research the issue & Send fix

[surapunoyousei]

Fixed