Trusted-click-element can't click an element in about:blank iframe #2963

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 an issue with YouTube, Facebook or Twitch.
• 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

trusted-click-element cannot click the GDPR dialog that is in about:blank iframe.

A specific URL where the issue occurs.

https://urshunt.tumblr.com/

Steps to Reproduce

1. Add: tumblr.com##+js(trusted-click-element, .components-button.is-primary)
2. Open https://urshunt.tumblr.com/

Expected behavior

I Agree! button would be clicked.

https://github.com/uBlockOrigin/uBlock-issues/assets/17256841/65cee985-7bc7-44cf-a2ca-12b174a6bc25

Actual behavior

It's not clicked.

uBO version

1.53.5rc10

Browser name and version

FF 119.0.1

Operating System and version

Windows 10