Fix separator background yet again.

git-svn-id: https://plugins.svn.wordpress.org/admin-menu-editor/trunk@949524 b8457f37-d9ea-0310-8a92-e5e31aec5664
Fix "&nbsp;" showing up in the "Menu title" field for items with no title. That entity should only be used for the header display.

git-svn-id: https://plugins.svn.wordpress.org/admin-menu-editor/trunk@949528 b8457f37-d9ea-0310-8a92-e5e31aec5664