Using: Firefox 34.0.5, MS Windows XP SP3
Firefox Add-ons: Flashblock 1.5.18, AdBlock Plus 2.6.6, NoScript 2.6.9.10,
Restore View Source for Firefox 6+ 0.1

Most videos on youtube are blocked as per functionality; however, attempting to
release specific block on flashblock'ed element (main player) is disabled.  

Clicking on the "F" icon in middle of flash item, for purposes of releasing
specific block, is inoperative.

The defect is reproducible on Firefox 34.0.5 (MacOSX 10.10) with NoScript
2.6.9.10.

I second that. I have seen some crappy websites where I was unable to click
"play" to ublock flash. But youtube was alaways good.

Now Youtube has failed. I saw many people complaining too at add-on review page

Firefox 34.0.5, Linux (AdBlock also used if it matters)

Same problem, Linux, Firefox 34.0.5, Flashblock 1.5.18 , neither Adblock nor
NoScript.  Youtube videos do not unblock; clicking the f has no effect.

I can confirm this bug on Linux Mint x86_64, Firefox 34.0, FlashBlock 1.5.18.
FlashBlock successfully blocks Flash, but clikcing the "F" does not start the
video.

I've tried deleting my whole profile and installing *only* FlashBlock to rule
out any interference by other plugins and the bug still triggers.

Note that this bug has been existent for some time (FlashBlock not realizing
that one clicked the "F"), but on YouTube it always worked (for me it never
worked on Vine, for example, but I personally think Vine is complete shit and
so it didn't annoy me). It appears YouTube has changed something about their
page layout and now the bug also appears on YouTube.

Please fix this. The web is damn near unusable without FlashBlock. I tried
numerous alternatives (FlashStopper, FlashDisable) but they're all shit.
Please, FlashBlock devs, you're our only hope. Please look into this issue.
Thanks.

Using FF ESR 24.7 and 24.8.1 with Flashblock 1.5.18

Same problem since end of December. Klicking on the f on youtube videos doesn't
play them.

It seems like there is some kind of layer over the video and the Flashblock
symbol because it does not change on mouseover as it normally does. I mean the
change from f to a play-triangle.

Hope this can get fixed soon! Thanks!!!

So I've done a bit of digging and indeed it is related to the CSS that YouTube
currently uses (and thus also, as I have stated before, the bug was already
present and only now shows because they apparently changed their CSS).

If you look at the YouTube page, you'll see a structure like this

[...]
<div id="player">
   <div id ="theater-background" />
   <div id="player-mole-container">
     [...]
  </div>
  <div id="content">
     [...]
  </div>
</div>

Now when you go to the "theater-background" div and use FireBug to inactivate
the CSS attribute "position: absolute" of #theater-background the video moves
down and the page looks messed up -- but now FlashBlock works.

Maybe it has to do that due to some weird CSS, the Z-index of some invisible
shit is overlaying the FlashBlock "F" and thus the click event gets sent to
/dev/null instead of FlashBlock? Just brainstorming here.

So I've turned my discovery into a GreaseMonkey script workaround:


// ==UserScript==
// @name        YouTube FlashBlock Workaround
// @namespace   http://youtube.com
// @include     https://www.youtube.com/*
// @include     http://www.youtube.com/*
// @version     1
// @grant       none
// ==/UserScript==

e = document.getElementById("theater-background");
if (e != null) {
  e.style.position = "relative";
}


It's a shitty workaround, but it'll keep FlashBlock working for me on YouTube
until this is finally fixed.

I can also confirm this is reproducible on Firefox 35.0 (MacOSX 10.9) when
viewing a video on YouTube.com but if a video is embedded, it works as it
should when you click to release the block. 

See
http://techcrunch.com/2015/01/13/firefox-35-launches-with-simplified-hello-video-chat-service/ 

(In reply to comment #7)
> So I've turned my discovery into a GreaseMonkey script workaround:
> 
> 
> // ==UserScript==
> // @name        YouTube FlashBlock Workaround
> // @namespace   http://youtube.com
> // @include     https://www.youtube.com/*
> // @include     http://www.youtube.com/*
> // @version     1
> // @grant       none
> // ==/UserScript==
> 
> e = document.getElementById("theater-background");
> if (e != null) {
>   e.style.position = "relative";
> }
> 
> 
> It's a shitty workaround, but it'll keep FlashBlock working for me on YouTube
> until this is finally fixed.
> 

Thank you, this worked for me. :) Hopefully something systematic can be done
later.

Hiding the DIV altogether works just as well and leaves the page intact. (If
this messes with some functionality, I’m not aware of it.)

@-moz-document domain("youtube.com") {

#theater-background {
    display: none ! important;
    }
}

Paste this in your userContent.css, or install Stylish and visit
http://userstyles.org/styles/109451/flashblock-fix-for-youtube

I had no idea you guys were discussing this here until a couple days ago or so.
I believe a correction may be needed to JRandomNoob's post.  I think it needs
to be "!important" and not "! important".  If both work, let me know. I've only
used and seen !important.

Prior to seeing this site, I made a how-to article for this fix, started as
early as 10th, and replaced once on the 23rd.  Even a none technical person
should be able to make use of it.

I've indicated to put just "#theater-background {display:none}" in the
userContent.css file, and this seems to work just fine for people on various
OSs and versions of FF. Plus a more broad entry like that allows the effect to
occur on other sites making use of the same technique used by Youtube.
If interested, or you need a more visual reference, the final (a couple of
revisions done) fix article is at
http://technotes.whw1.com/computer-related/software/internet-browsers/firefox/69-fix-for-firefox-flashblock-and-youtube-click-problem 
Provided so you won't have to to roam through the whole site once it gets
buried.
Of course the audience is much broader than here and so I had to go into where
the file is and how to access, etc.