Funnily enough I'm making a site theme and nothing I do can detect this one element but this add-on can.

It's great because my theme now completely works, less great because this add-on hides all the rules it's given: I can't take whatever it's found and implement it myself. This situation has happened multiple times and it's beginning to get a little grating.

I know the author has said they're planning on adding these but that was originally stated 2 years ago. Unfortunately until those features are here I can only give it a(n albeit very strong) 4 stars.

Edit: Like the developer says the feature to see each blocked element and select them individually is now implemented! I have no other complaints, this is the best add-on I've found of its type. An easy 5 stars. Thank you for updating it <3