Make it clearer when custom filters are disabled

[whatuserever]

Prerequisites

• I verified that this is not a filter list issue. Report any issues with filter lists or broken website functionality in the uAssets issue tracker.
• This is NOT a YouTube, Facebook or Twitch report. These sites MUST be reported by clicking their respective links.
• This is not a support issue or a question. For support, questions, or help, visit /r/uBlockOrigin.
• I performed a cursory search of the issue tracker to avoid opening a duplicate issue.
• The issue is not present after disabling uBO in the browser.
• I checked the documentation to understand that the issue I am reporting is not normal behavior.

I tried to reproduce the issue when...

• uBO is the only extension.
• uBO uses default lists and settings.
• using a new, unmodified browser profile.

Description

This is a followup to #3161.

I installed Mullvad Browser today, which comes bundled with uBlock Origin. As I started using it, I experienced odd behavior with uBlock Origin:

1. The element picker was not available.
2. The Block element... was gone from the context menu
3. Custom filters were not working.

This is because My filters is disabled by default with Mullvad Browser, and I had some trouble understanding this is the case as this is not default uBlock Origin behavior.

A specific URL where the issue occurs.

https://mullvad.net/en/browser

Steps to Reproduce

1. Disable the My filters list in the Filters list tab
2. Forget you have My filters disabled
3. Try to block an element / use the element picker / add a new custom filter

Expected behavior

It should be clear all of these are unavailable because My filters is disabled.

Actual behavior

The only indication is the Enable my custom filters option in the My filters tab, which can be easily overlooked.

Suggestions

1. Show the element picker icon in a disabled/inactive state. Change the description on hover to something along the lines of "Enable custom filters to use element picker"
2. Make the editor in My filters readonly if custom filters are disabled.
   • To support edits without enabling My filters, add an Edit button to enable editing with a disclaimer that the list will not take effect unless custom filters are enabled
     • Maybe even add an option for "I understand, don't show this again" for those who really like editing their filters without using them?

uBO version

1.61.2

Browser name and version

Mullvad Browser 14.0.4 (based on Mozilla Firefox 128.6.0esr)

Operating System and version

OS: Ubuntu 24.04.1 LTS

[gwarser]

AFAIK you are not supposed to change any settings in Mullavad to prevent fingerprinting.

"harden uBO against fingerprinting" Mullavad issue: https://gitlab.torproject.org/tpo/applications/mullvad-browser/-/issues/164

Your suggestions look reasonable (at least the top ones).

The only indication is the Enable my custom filters option in the My filters tab, which can be easily overlooked.

Also, the entry on "Filter lists" tab.