If you use WordPress’ Distraction Free Writing Mode every day, then you may have noticed a small bug where the editor gets chopped off at smaller screen sizes. Chances are that most people don’t use the DFW mode on mobile devices very often, so the bug seems to have gone unnoticed for a little while.
The good news is that this will be fixed in WordPress 3.9. Janneke Van Dorpe submitted a patch for the issue with a simple CSS fix that makes the zen writing mode responsive.
It’s also worth mentioning that the “fullscreen” button has been removed in favor of a fullscreen icon for launching Distraction Free Writing mode:
There are several compelling reasons why using the Distraction Free Writing mode can improve the quality of your writing and help you to write more efficiently. The CSS housekeeping fixes in 3.9 will make the zen mode writing experience even better if you happen to be using a tiny browser window or blogging from a mobile device.