#600 Fix Wordpress's admin menu issue in Chrome 45

If you noted, the admin menu of WordPress (4.3) is messed in Chrome (v45):

According to a StackOverflow post there is a known bug in chrome (more info here). The source of the problem stems from Slimming Paint which is enabled by default in Chrome 45. Disabling slimming paint fixes the issue.

To disable this feature, visit chrome://flags/#disable-slimming-paint in Chrome and Enable the Disable slimming paint option, and make sure the other two Enable options are disabled because they will override the Disable option.

Hopefully, it will be fixed in Chrome version 47.

For now, you can do as following to solve this issue: add this in your template's functions.php (single site) or in mu-plugins/functions.php (multisite):

function admin_menu_fix() {
    echo '<style>
    #adminmenu { transform: translateZ(0); }
add_action('admin_head', 'admin_menu_fix');

[0] http://stackoverflow.com/questions/32420917/wordpress-admin-menu-messed
[1] http://premium.wpmudev.org/forums/topic/global-css-for-all-sites-in-the-multisite