Cannot inspect inside iframes with logger inspector

[laniakea64]

Describe the issue

It is not possible to determine which cosmetic filter(s) are hiding a specific element inside an iframe. The logger inspector appears to have no way to inspect the contents of iframes.

Screenshot in which the issue can be seen

Steps for anyone to reproduce the issue

1. Dashboard > My Filters, add this filter -

###goButton

2. Open the logger
3. Visit https://developer.mozilla.org/en-US/docs/Web/HTML/Element/iframe#Example1 . Notice that the button inside the iframe is hidden.
4. Go back to the logger, and open the logger inspector and try to find the hidden button.

(Some related discussion on mozillaZine: http://forums.mozillazine.org/viewtopic.php?p=14766503#p14766503 )

Your settings

• Browser/version: Firefox 55.0.3 or SeaMonkey 2.49.1, new profile
• uBlock Origin version: 1.14.11b2 (legacy). Also happens with uBO/webext 1.14.11b2 in Firefox.

Your filter lists

default

Your custom filters (if any)

see steps-to-reproduce