Menus Admin Screen Doesn't Accept Body Classes

[JohnONolan]

This is going to be a hazy bug report, because it's at the outer limits of my technical ability, but:

Using this code

function my_admin_body_class( $classes ) {
	if ( is_admin() ) {
		$classes .= 'extra-class';
	}
	return $classes;
}
add_filter('admin_body_class', 'my_admin_body_class');

I can add a class of "extra-class" to the admin body tag on every single page... except Appearance > Menus. Where the class doesn't get inserted at all.

I'm seeing this both in 3.2 and latest trunk. Apologies if this is something I'm doing wrong... like I say - outer limits.

Confirmed. The culprit is lines 435-440 in wp-admin/nav-menus.php which is treating admin_body_class as an action instead of a filter and not returning anything.

Damnit, beaten by Sergey ;-)

Same for Widgets screen in the accessibility mode:
http://core.trac.wordpress.org/browser/tags/3.2.1/wp-admin/widgets.php#L26

A workaround could be calling the function with a later priority and with a whitespace in the string:

function my_admin_body_class( $classes ) {
	if ( is_admin() ) {
		$classes .= ' extra-class';
	}
	return $classes;
}
add_filter('admin_body_class', 'my_admin_body_class', 11);

Geeze, SergeyBiryukov even beats me these days!

I've just gone through checking this whilst you guys were busy posting, Widgets and Menu's are the only location which overwrites, menu uses add_action rather than add_filter and iframe's don't get the admin_body_class filter at all (and are missing the wp-admin class too)

(no need to patch the iframe code btw, I've got it changed already!)

You guys are all insanely quick. Also - I'm glad I'm not a complete moron after all. Well, you know, at least in this context.

Fixes admin_body_class on Widgets screen as well

In [18882]:

Fix admin_body_class filter for Menu's and Widgets pages, Include the filter in Iframe's. Props SergeyBiryukov & johnbillion. Fixes #18853