Fraidycat postMessage errors on localhost

[poacher2k]

Hi!

Thank you for this brilliant extension, enjoying it a ton :)

• [x] I have checked the Common Problems page.
• [x] I have searched the issue tracker for a bug that matches the one I want to file, without success.

Desktop:

• OS: Mac
• Browser Firefox
• Version 89

Description: Fraidycat fails to execute ‘postMessage’ on ‘DOMWindow’ on localhost. I get this on every refresh while developing locally. Disappears when I disable Fraidycat.

[kickscondor]

Sweet! Thank you - will push out this fix soon.