Ublock: Firefox Reader view circumvents uBO's no-large-media block

[RoxKilly]

Describe the issue

In Firefox, when I switch to reader view, images that should be blocked by uBO's no-large-media: * true are not blocked.

One or more specific URLs where the issue occurs

https://jotter.jonathankingston.co.uk/blog/2017/04/04/containers-assignment/

Screenshot in which the issue can be seen

Dev tools - network panel of the regular page: browser connects but doesn't download

Logger of the regular page:

Dev tools after hitting Reader view icon: browser reconnects and downloads content

Logger of the page after hitting Reader View icon

Steps for anyone to reproduce the issue

1. Set no-large-media: * true rule
2. Go to https://jotter.jonathankingston.co.uk/blog/2017/04/04/containers-assignment/
3. You'll notice in the logger that content is blocked.
4. Click the Reader View icon at the far right of the URL bar
5. The images that should be blocked are downloaded (shown both in the browser's network panel and uBO's logger)

Your settings

• Browser/version: Firefox 53
• uBlock Origin version: 1.12.1

EDIT: I just noticed that the extension is fully disabled in Reader View (the uBO icon in the toolbar turns grey) so it seems this isn't an issue specific to images. This may be a browser imposed limitation. Am still posting in case I'm wong.

[gorhill]

uBO is disabled because the context is reader.about-scheme, and uBO is whitelisted by default for about-scheme. It works fine if un-whitelisted.

[gorhill]

Thinking more about it, I will try to see if I can provide the current context in the tooltip of uBO's power button, there is currently no obvious way to find out the current context was reader.about-scheme (have to go through the logger).

[Thorin-Oakenpants]

as per earthlng's comments here

matrix-off: about-scheme false
about-scheme * * allow
reader.about-scheme * * block
reader.about-scheme * image allow <==edited/added since post

[gorhill]

there is currently no obvious way to find out the current context was reader.about-scheme

Actually there is now, since the new popup panel was introduced in 1.27.0