In order to see the post meta boxes using Distraction-free Writing Mode in WordPress 4.1, you have to move the cursor away from the post editor. During the editing process, you may need to preview a post several times. Since the preview button is only available when the publish meta box is shown, you have to go in and out of DFW mode multiple times before publishing a post.
This can not only be annoying, but discourage you from using DFW mode altogether. Thankfully, there’s a handy plugin by Alex King that solves the problem by adding a preview button inside the post editor.
The preview button inside the editor significantly reduces the amount of times the DFW transition occurs. What’s nice about this plugin is that when you disable DFW mode, the preview button disappears in favor of the publish meta box.