Add more columns in the theme browser on screens over 2000px wide to ensure that theme screenshots never appear larger than their resolution allows. Fixes #26172, props shaunandrews.



git-svn-id: https://develop.svn.wordpress.org/trunk@26633 602fd350-edb4-49c9-b593-d223f7449a82
Avoid a PHP notice on Edit Menus screen when a menu is attached to a non-existing location.

props nofearinc.
fixes #26287.

git-svn-id: https://develop.svn.wordpress.org/trunk@26634 602fd350-edb4-49c9-b593-d223f7449a82