[Bug]: Adaptive Tab Bar Colour unable to change Floorp's color when using a custom userchrome

[julianpoelmann]

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

I just switch to Floorp. its been pretty nice but its been bother me that Adaptive Tab Bar Colour cannot change the main color of the Floorp window. ive redone an installation of the shyfox theme and settings and it works fine on the latest default firefox build but in floorp it just doesnt change it.

i have noticed that it stopped functioning once Shyfox is installed yet this behavior did not change on firefox. using the same older version in my firefox installation did not solve this either

Changing the tab design didnt resolve this either. Floorp does restore functionality to floating menu elements (Adress bar can float and side bar which did broke on firefox)

Reproduction Steps

1. Use a vertical tab manager
2. Install Adaptive Tab Bar Colour
3. Install Shyfox
4. Restart Floorp

Expected Behavior

In the image on the right it behaves as expected

Actual Behavior

In the image on the left is what happens

Screenshots

(Ignore the cookie selection on the left, that did not affect the colours in this case as seen by other ui elements)

Browser Version

11.22.0 (64-bits)

Operating System

Windows 11 Pro for workstations

Additional Context

Reporting this as it simply does not happen in firefox but only in floorp