WordPress 4.5 “Coleman” was released last week without too many issues. However, the WordPress development team recently identified two bugs that are prompting an immediate point release scheduled for next week.
The first is that TinyMCE toolbars and tabs are unresponsive in Chrome Version 50.0.2661.75 beta-m (64-bit). The second is that page templates with widgets are styled incorrectly. WordPress 4.5 added a singular class that many themes use, including Twenty Eleven, that breaks a site’s layout. After a lengthy discussion and testing, the decision was to revert the change.
WordPress 4.5.1 RC 1 is available and the core team wants as many people as possible to test the TinyMCE update and other bug fixes included in the release. If you think you’ve discovered a bug, you’re encouraged to report it in the Alpha/Beta section of the support forums.