Element picker & zapper mode not working

[pepablock]

Describe the issue

If I try to use either of these I just get a blank overlay all over the page and nothing happens. And I have to refresh the page to see the content again. I made a short gif to show what I mean, see below. Also, I think I'm not the only one experiencing this problem, see: https://www.reddit.com/r/uBlockOrigin/comments/7cy3rv/element_blocker_doesnt_work_in_firefox_57/ https://www.reddit.com/r/uBlockOrigin/comments/7ehtdc/element_picker_doesnt_work_anymore/

One or more specific URLs where the issue occurs

Everywhere

Screenshot in which the issue can be seen

Steps for anyone to reproduce the issue

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Your settings

• OS/version: macOS High Sierra/10.13.1
• Browser/version: Firefox Quantum 57.0 (64-bit)
• uBlock Origin version: 1.14.18

Your filter lists

Default filter lists + CZE, SVK: EasyList Czech and Slovak

Your custom filters (if any)

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[gorhill]

Unable to reproduce. Try in a new profile with uBO alone -- no other extension.

[gorhill]

Also, you seem to have a modified version of uBO, the power button color does not match the color used in the original version.

[f4grx]

confirmed to be broken in win10 too, and ublock origin is the only installed extension. I dont even have an overlay. Nothing happens.

[gorhill]

I dont even have an overlay.

Did you inspect the DOM? To me it looks like uBO's transparent iframe overlay might be re-styled by some user styles on your side?

[slorquet]

I dont know what to search for in the DOM.

it still works with a new profile, but not in my current profile. I have no idea what has broken my profile but it's not an extension.

Maybe a "migration process" from firefox 56 to 57 has broken it...

Now the only option to make ublock work again is too loose all by bookmarks and history

[gorhill]

I am pretty sure you have user styles overriding uBO's own styles. You will have to look into this. See if you have a userContent.css file in your profile, and its content if so: http://kb.mozillazine.org/index.php?title=UserChrome.css.

[f4grx]

I dont have a single css file anywhere in my firefox profile. I am using firefox with default settings, not pretty customization at all.

dom inspector does not show inclusion of any userContent.css

note: uninstalling ublock then reinstalling does not help

[gorhill]

I dont know what to search for in the DOM.

Look for a iframe at the bottom of the document, uBO inserts its iframe before the closing html tag. If it's there, then select the iframe and see what rule is being applied to it in the CSS styles inspector.

[f4grx]

I got it working again, that is strange.

I had other tabs with contents not reloaded yet after a crash. opening these tabs so that their DOM was loaded seem to have fixed the issue.

This is very weird for me. Does it make sense to you?

even stranger the fix seems to be permanent, I cannot reproduce the issue anymore.

PS: yes, now I see the inserted iframe at the bottom of the DOM inspector before closing html tag (and it pops up very visibly), but when it was broken, clicking on the element picker did NOT add this iframe.

[gorhill]

Does it make sense to you?

No. Seems to be a Firefox specific quirk possibly due to the tab being in the same content process as some other tabs which were suspended? I can only speculate.

[pepablock]

Sorry for a late response.

See if you have a userContent.css file in your profile, and its content if so: http://kb.mozillazine.org/index.php?title=UserChrome.css.

That was the case for me, I had this code inside of my userContent.css file causing the problem. I used this to get a blank page after opening a new tab. I guess from now I will use an add-on for that instead.

@-moz-document url(about:blank), url(about:newtab) {
    * {
        display: none !important;
    }
}

Also, you seem to have a modified version of uBO, the power button color does not match the color used in the original version.

What color is default? I don't remember modifying it at all.