We recently upgraded our network to WordPress 3.8.1, and one of our users reported an issue with WP Glossary. Because of the responsive design of the new WordPress interface, the editor window in the middle column can shrink all the way down to 420 pixels-wide at lower resolutions.
With WP Glossary active, the wpglossary select menu in the TinyMCE toolbar prevents the editor window from reducing its width below 520 pixels-wide, so the right sidebar widgets (Publish, Format, Categories, Tags, etc.) overlap the editor window.
This is a minor issue, and I advised the site owner that a temporary workaround is to collapse the left admin menu. I just wanted get the issue up on the support forum.
The user who reported this is running Firefox on a Windows 2000 laptop at 1024x768, but I was able to reproduce the issue by shrinking the window on my Mavericks copy of Firefox.