Title: Small problem with Firefox Last modified: January 24, 2018 --- # Small problem with Firefox * [sdawales](https://wordpress.org/support/users/sdawales/) * (@sdawales) * [8 years, 4 months ago](https://wordpress.org/support/topic/small-problem-with-firefox/) * Hi guys, * Just when I thought I’d got it, I’ve run into an issue while testing with Firefox 58 and I assume on other versions. My blog page works as intended on IE, Edge, Chrome. After further testing on Opera & Firefox the page initially displays correctly. If I navigate away from the page then navigate back, the body of the page shows my background color and I cannot see the listings of blogs although the links appear to be there since the page is clickable to an actual blog post. Hitting ctrl + f5 displays the page correctly again. * Between each step of the process, I did clear cache. When I disable AO, the issues goes away. I then re-enable and confirm the issue is back. I then disabled inline and defer and the issue was resolved. I re-enable inline and defer and the problem returns to Firefox but I am not able to reproduce on again on Opera. * At this point, I know this has to do with my critical path css. The only issue I have is what? I won’t post that here unless someone wants to take a look at it but has anyone come across a similar bug that could give me a pointer? It seems a shame that it is a single page and disabling inline and defer is not an option at this point. * I have not checked any of this on a Mac with safari yet. * The page I need help with: _[[log in](https://login.wordpress.org/?redirect_to=https%3A%2F%2Fwordpress.org%2Fsupport%2Ftopic%2Fsmall-problem-with-firefox%2F%3Foutput_format%3Dmd&locale=en_US) to see the link]_ Viewing 9 replies - 1 through 9 (of 9 total) * Plugin Author [Optimizing Matters](https://wordpress.org/support/users/optimizingmatters/) * (@optimizingmatters) * [8 years, 4 months ago](https://wordpress.org/support/topic/small-problem-with-firefox/#post-9902319) * That is a _very_ hard to troubleshoot issue I’m afraid. I can see your post display is being done using JavaScript (your page is also black when JS is disabled), so could you disable JS optimization for a second to see if the problem also occurs in that case? * Thread Starter [sdawales](https://wordpress.org/support/users/sdawales/) * (@sdawales) * [8 years, 4 months ago](https://wordpress.org/support/topic/small-problem-with-firefox/#post-9903231) * Unfortunately, that didn’t help. It’s back on now but after disabling and clearing the cache and trying in a private tab on FF, I get the same result. * Plugin Author [Optimizing Matters](https://wordpress.org/support/users/optimizingmatters/) * (@optimizingmatters) * [8 years, 4 months ago](https://wordpress.org/support/topic/small-problem-with-firefox/#post-9903554) * OK … next up; can your remove the critical CSS but keep “inline & defer” active to see if in that case the problem remains or not (you’ll see your content “flash” due to it being shown without CSS first, but this is just for testing purposes, not a fix)? * Thread Starter [sdawales](https://wordpress.org/support/users/sdawales/) * (@sdawales) * [8 years, 4 months ago](https://wordpress.org/support/topic/small-problem-with-firefox/#post-9903611) * Thank you for the reply. I removed the critical path css, saved and flushed cache then tested on IE, Edge, Chrome, FF, Opera and while I had the flash you commented on, there was no change. I guess I can rule out CPS? Thank you for your continued effort. * Plugin Author [Optimizing Matters](https://wordpress.org/support/users/optimizingmatters/) * (@optimizingmatters) * [8 years, 4 months ago](https://wordpress.org/support/topic/small-problem-with-firefox/#post-9903923) * > there was no change * so in FF you still had the black background, right? * > I guess I can rule out CPS? * CPS being? * Thread Starter [sdawales](https://wordpress.org/support/users/sdawales/) * (@sdawales) * [8 years, 4 months ago](https://wordpress.org/support/topic/small-problem-with-firefox/#post-9903950) * Sorry, I mean css. Critical path css. and yes, FF still had the black. - This reply was modified 8 years, 4 months ago by [sdawales](https://wordpress.org/support/users/sdawales/). * Plugin Author [Optimizing Matters](https://wordpress.org/support/users/optimizingmatters/) * (@optimizingmatters) * [8 years, 4 months ago](https://wordpress.org/support/topic/small-problem-with-firefox/#post-9904649) * Indeed, this confirms the problem is not with your Critical CSS, but probably due to how the full CSS is loaded. I happened to update the code that does that to the latest specs of [Filementgroup’s LoadCSS](https://github.com/filamentgroup/loadCSS#readme) last week, could you [download and install AO’s development-version](https://github.com/futtta/autoptimize/archive/master.zip)( has other improvements as well) and see if this improves anything? * Thread Starter [sdawales](https://wordpress.org/support/users/sdawales/) * (@sdawales) * [8 years, 4 months ago](https://wordpress.org/support/topic/small-problem-with-firefox/#post-9905645) * It didn’t appear to change anything unfortunately. Still the same issue. A ctrl + f5 refresh will display the content of the page but that’s about the only way I can get it to render correctly but as soon as I navigate away, then come back, it is back to the black screen. Crazy that it is only a single page. * Plugin Author [Optimizing Matters](https://wordpress.org/support/users/optimizingmatters/) * (@optimizingmatters) * [8 years, 4 months ago](https://wordpress.org/support/topic/small-problem-with-firefox/#post-9906047) * Wow … this is turning out to be a freaky problem :-/ * Somehow part of the deferred CSS is not being applied when going back to the blog overview (which has a very specific layout) in Firefox. * Only thing I can think of for now is to disable “inline & defer” for that specific page, using this code snippet [@sdawales](https://wordpress.org/support/users/sdawales/); * ``` add_filter('autoptimize_filter_css_defer','dont_defer_blogoverview'); function dont_defer_blogoverview() { error_log($_SERVER['REQUEST_URI']); if ($_SERVER['REQUEST_URI'] === '/blog/') { return false; } else { return true; } } ``` Viewing 9 replies - 1 through 9 (of 9 total) The topic ‘Small problem with Firefox’ is closed to new replies. * ![](https://ps.w.org/autoptimize/assets/icon-256X256.png?rev=2211608) * [Autoptimize](https://wordpress.org/plugins/autoptimize/) * [Frequently Asked Questions](https://wordpress.org/plugins/autoptimize/#faq) * [Support Threads](https://wordpress.org/support/plugin/autoptimize/) * [Active Topics](https://wordpress.org/support/plugin/autoptimize/active/) * [Unresolved Topics](https://wordpress.org/support/plugin/autoptimize/unresolved/) * [Reviews](https://wordpress.org/support/plugin/autoptimize/reviews/) * 9 replies * 2 participants * Last reply from: [Optimizing Matters](https://wordpress.org/support/users/optimizingmatters/) * Last activity: [8 years, 4 months ago](https://wordpress.org/support/topic/small-problem-with-firefox/#post-9906047) * Status: not resolved