Last week alot of people had a problem with their WordPress admin menu.
Wp admin menu did break and looked very weird. This was only seen by those with Chrome 45.0.2454.85.

Some suggested that you could fix this by changing settings in Chrome.
I my self didn’t like that i would have to change settings on every computer i use.
So instead i tried couple things just with css and find a better solution.
With mine solution you will have to only to add code inside functions.php and WordPress admin menu should work on all your computers.

Here is the WordPress Admin Menu bug fix / solution

Go to your functions.php.

Add this code.

function custom_css_code_backend() {
echo ‘<style type=”text/css”>
#adminmenu li {
display: block;
transform: translateZ(0);

}
</style>’;
}

add_action(‘admin_head’, ‘custom_css_code_backend’);

 

What will this CSS code do on your WordPress website?
It will add that css code to your admin header and make each of li (list items) to be blocks.
Good to know after WordPress Admin Menu bug fix inside functions.php ?

I noticed that on one of mine websites i had to log out and login to see the changes.
You can try also to to one of these shortcuts before logout because it may work.

Windows / Linus: CTRL + SHIFT + R or CTRL + F5
Mac: CMD + SHIFT + R

What this will do is that it will refresh admin page but ignore the cache.
That way you will get newest update of css.