Hierarchical taxonomy names starting with 'even' cause JS conflicts

[netweblogic]

Tested by a few independent users and easy to reproduce by pasting this in:

add_action('init','messed_up_categories',1);
function messed_up_categories(){
	register_taxonomy('evenscrewy',array ( 0 => 'post'), array( 
		'hierarchical' => true, 
		'label' => 'Screwy Categories',
		'show_ui' => true,
		'query_var' => true,
		'singular_label' => 'Screwy Category'
	));
}

Cause:
Starting your taxonomy name with 'even' with any following combination of text will cause this issue, e.g. 'event-categories', 'events', 'eventcats' don't work, yet e.g. 'zeven' does.

Symptoms:
Go to your post (or any CPT) the above was added to and try creating a new category. When you click the 'add category' button, the button appears in the list of taxonomies instead of the new name.

[SergeyBiryukov]

#21106, #21152