Is there a list of themes confirmed to work fully with WPforo? The themes you develop/test on?

wpForo developers have made the plugin maximumly compatible with other WordPress plugins and themes. There are a little number of plugins/themes that conflict with wpForo. All these topics can be found under the plug-in conflict tag.

https://wpforo.com/community/?wpfin=tag&wpfs=plugin%20conflict

Or is there more code I can edit to fix this on mobile?

I have a feeling that if I buy the theme and ask support, they're not going to help me with a plugin. 

What's up with the Kale theme on mobile that the desktop fix didn't work on mobile? 

This issue doesn't come form wpForo Advanced Attachments add-on, to make sure, just switch to some default theme and check again. The theme develops should know the best way to solve the issue. As you may see the code provided by our developers solve the issue partially. 

Or is there more code I can edit to fix this on mobile?

I have a feeling that if I buy the theme and ask support, they're not going to help me with a plugin. 

What's up with the Kale theme on mobile that the desktop fix didn't work on mobile? 

This issue doesn't have any relation to wpForo. It comes from your theme. You should contact theme support.  

Please try to check it using other devices. Probably it's a cache issue. 

Please follow these steps to get it resolved

1. Open the kale.js  file in \wp-content\themes\kale\assets\js folder

2. Find the function kale_responsive_videos() function and replace to the code I've provided below

function kale_responsive_videos(){
    YOUTUBE_VIDEO_MARGIN = 5;
    jQuery('.single-content iframe, .page-content iframe').each(function(index,item) {
        var ifr_src = jQuery(item).attr('src');
        if(ifr_src && ifr_src.match(/(https?:)?\/\/www\.youtube\.com/)) {
            var w=jQuery(item).attr('width');
            var h=jQuery(item).attr('height');
            var ar = h/w*100;
            ar=ar.toFixed(2);
            //Style iframe
            jQuery(item).css('position','absolute');
            jQuery(item).css('top','0');
            jQuery(item).css('left','0');
            jQuery(item).css('width','100%');
            jQuery(item).css('height','100%');
            jQuery(item).css('max-width',w+'px');
            jQuery(item).css('max-height', h+'px');
            jQuery(item).wrap('<div style="max-width:'+w+'px;margin:0 auto; padding:'+YOUTUBE_VIDEO_MARGIN+'px;" />');
            jQuery(item).wrap('<div style="position: relative;padding-bottom: '+ar+'%; height: 0; overflow: hidden;" />');
        }
    });
}

3. Delete all caches:

• If you use some cache plugins delete those plugins caches
• Navigate to Dashboard > Forum > Dashboard click on button.
• Press CRTL+F5 (twice) on forum frontend and check again.

Thanks. Sent

Please install and activate the Duplicator — WordPress Migration Plugin, backup your WordPress site and send it to infogvectors.com email address to allow us to check it.