I observed that embedded blog posts are no longer loading when the site is viewed with Chrome-based browsers. This is serious, and nobody seems to be talking about it!
At the bottom of it all, be aware of how the platform stores the app data. This advice helped me to debug a perplexing issue.
A change in Google Fonts' URI structure for embedding combined fonts can lead to an incompatibility with WordPress.
When you muck around with PHP enough, every now and then you'll find a skeleton in the closet.
Enable WordPress AJAX requests to set the language locale through WPML with this small patch.
An interesting gotcha that I stumbled across recently, sending a 404 response code with a download forced by Content-Disposition: attachment will fail but inline content will still be displayed. This behaviour was tested in both Chrome and FireFox.
Of course the appropriate response code should always be sent; this 404 response code was being sneaked in by WordPress and led to hours of frustration.